161247221136 has 135 divisors (see below), whose sum is σ = 456934693761. Its totient is φ = 53082490752.

The previous prime is 161247221129. The next prime is 161247221143. The reversal of 161247221136 is 631122742161.

The square root of 161247221136 is 401556.

It is a perfect power (a square), and thus also a powerful number.

161247221136 is a `hidden beast` number, since 1 + 61 + 247 + 221 + 136 = 666.

161247221136 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (161247221129) and next prime (161247221143).

It can be written as a sum of positive squares in only one way, i.e., 112388539536 + 48858681600 = 335244^2 + 221040^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 161247221136.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 525235095 + ... + 525235401.

Almost surely, 2^161247221136 is an apocalyptic number.

161247221136 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

161247221136 is the 401556-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161247221136

161247221136 is an abundant number, since it is smaller than the sum of its proper divisors (295687472625).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161247221136 is an equidigital number, since it uses as much as digits as its factorization.

161247221136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 846 (or 421 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

Multiplying 161247221136 by its sum of digits (36), we get a square (5804899960896 = 2409336²).

161247221136 divided by its sum of digits (36) gives a square (4479089476 = 66926²).

Adding to 161247221136 its reverse (631122742161), we get a palindrome (792369963297).

The spelling of 161247221136 in words is "one hundred sixty-one billion, two hundred forty-seven million, two hundred twenty-one thousand, one hundred thirty-six".