16161221640 has 128 divisors (see below), whose sum is σ = 49721299200. Its totient is φ = 4201021440.

The previous prime is 16161221627. The next prime is 16161221669. The reversal of 16161221640 is 4612216161.

It is a super-2 number, since 2×16161221640² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 16161221598 and 16161221607.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 747624 + ... + 768936.

It is an arithmetic number, because the mean of its divisors is an integer number (388447650).

Almost surely, 2^16161221640 is an apocalyptic number.

16161221640 is a gapful number since it is divisible by the number (10) 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 16161221640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24860649600).

16161221640 is an abundant number, since it is smaller than the sum of its proper divisors (33560077560).

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

16161221640 is a wasteful number, since it uses less digits than its factorization.

16161221640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21487 (or 21483 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The spelling of 16161221640 in words is "sixteen billion, one hundred sixty-one million, two hundred twenty-one thousand, six hundred forty".