16565509680 has 80 divisors (see below), whose sum is σ = 53009654784. Its totient is φ = 4274968320.

The previous prime is 16565509621. The next prime is 16565509729. The reversal of 16565509680 is 8690556561.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×16565509680² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1105834 + ... + 1120713.

Almost surely, 2^16565509680 is an apocalyptic number.

16565509680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16565509680 is an abundant number, since it is smaller than the sum of its proper divisors (36444145104).

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

16565509680 is a wasteful number, since it uses less digits than its factorization.

16565509680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2226594 (or 2226588 counting only the distinct ones).

The product of its (nonzero) digits is 1944000, while the sum is 51.

The spelling of 16565509680 in words is "sixteen billion, five hundred sixty-five million, five hundred nine thousand, six hundred eighty".