21515345712 has 150 divisors (see below), whose sum is σ = 72438666828. Its totient is φ = 6147223488.

The previous prime is 21515345681. The next prime is 21515345773. The reversal of 21515345712 is 21754351512.

21515345712 is a `hidden beast` number, since 2 + 1 + 51 + 5 + 34 + 571 + 2 = 666.

It is a super-2 number, since 2×21515345712² (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 an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 105898 + ... + 232905.

Almost surely, 2^21515345712 is an apocalyptic number.

It is an amenable number.

21515345712 is an abundant number, since it is smaller than the sum of its proper divisors (50923321116).

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

21515345712 is a wasteful number, since it uses less digits than its factorization.

21515345712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338837 (or 338815 counting only the distinct ones).

The product of its digits is 42000, while the sum is 36.

The spelling of 21515345712 in words is "twenty-one billion, five hundred fifteen million, three hundred forty-five thousand, seven hundred twelve".