21642561324 has 36 divisors (see below), whose sum is σ = 54780500320. Its totient is φ = 7204572000.

The previous prime is 21642561299. The next prime is 21642561337. The reversal of 21642561324 is 42316524612.

21642561324 is a `hidden beast` number, since 2 + 1 + 64 + 2 + 561 + 32 + 4 = 666.

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

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 373219 + ... + 427290.

Almost surely, 2^21642561324 is an apocalyptic number.

It is an amenable number.

21642561324 is an abundant number, since it is smaller than the sum of its proper divisors (33137938996).

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

21642561324 is a wasteful number, since it uses less digits than its factorization.

21642561324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 801270 (or 801265 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The spelling of 21642561324 in words is "twenty-one billion, six hundred forty-two million, five hundred sixty-one thousand, three hundred twenty-four".