16565721012 has 36 divisors (see below), whose sum is σ = 41964170976. Its totient is φ = 5510077200.

The previous prime is 16565720947. The next prime is 16565721023. The reversal of 16565721012 is 21012756561.

16565721012 is a `hidden beast` number, since 1 + 6 + 565 + 72 + 10 + 12 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×16565721012² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 475864 + ... + 509487.

It is an arithmetic number, because the mean of its divisors is an integer number (1165671416).

Almost surely, 2^16565721012 is an apocalyptic number.

16565721012 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

16565721012 is an abundant number, since it is smaller than the sum of its proper divisors (25398449964).

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

16565721012 is a wasteful number, since it uses less digits than its factorization.

16565721012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 985828 (or 985823 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 16565721012 in words is "sixteen billion, five hundred sixty-five million, seven hundred twenty-one thousand, twelve".