21546256464 has 30 divisors (see below), whose sum is σ = 60299593146. Its totient is φ = 7182085440.

The previous prime is 21546256453. The next prime is 21546256477. The reversal of 21546256464 is 46465264512.

21546256464 is a `hidden beast` number, since 2 + 15 + 4 + 625 + 6 + 4 + 6 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16811715600 + 4734540864 = 129660^2 + 68808^2 .

It is a super-2 number, since 2×21546256464² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 74813247 + ... + 74813534.

Almost surely, 2^21546256464 is an apocalyptic number.

21546256464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21546256464 is an abundant number, since it is smaller than the sum of its proper divisors (38753336682).

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

21546256464 is a wasteful number, since it uses less digits than its factorization.

21546256464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149626795 (or 149626786 counting only the distinct ones).

The product of its digits is 1382400, while the sum is 45.

The spelling of 21546256464 in words is "twenty-one billion, five hundred forty-six million, two hundred fifty-six thousand, four hundred sixty-four".