16003981561 has 16 divisors (see below), whose sum is σ = 17115926400. Its totient is φ = 14919811200.

The previous prime is 16003981549. The next prime is 16003981579. The reversal of 16003981561 is 16518930061.

It is a cyclic number.

It is not a de Polignac number, because 16003981561 - 2⁵ = 16003981529 is a prime.

It is a super-2 number, since 2×16003981561² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16003981541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 718845 + ... + 740773.

It is an arithmetic number, because the mean of its divisors is an integer number (1069745400).

Almost surely, 2^16003981561 is an apocalyptic number.

It is an amenable number.

16003981561 is a deficient number, since it is larger than the sum of its proper divisors (1111944839).

16003981561 is a wasteful number, since it uses less digits than its factorization.

16003981561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22560.

The product of its (nonzero) digits is 38880, while the sum is 40.

The spelling of 16003981561 in words is "sixteen billion, three million, nine hundred eighty-one thousand, five hundred sixty-one".