161221752 has 96 divisors (see below), whose sum is σ = 456019200. Its totient is φ = 53361504.

The previous prime is 161221751. The next prime is 161221757. The reversal of 161221752 is 257122161.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161221751) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 464443 + ... + 464789.

It is an arithmetic number, because the mean of its divisors is an integer number (4750200).

Almost surely, 2^161221752 is an apocalyptic number.

161221752 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161221752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (228009600).

161221752 is an abundant number, since it is smaller than the sum of its proper divisors (294797448).

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

161221752 is a wasteful number, since it uses less digits than its factorization.

161221752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 607 (or 591 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 161221752 is about 12697.3127865702. The cubic root of 161221752 is about 544.2618314986.

The spelling of 161221752 in words is "one hundred sixty-one million, two hundred twenty-one thousand, seven hundred fifty-two".