21609543504 has 40 divisors (see below), whose sum is σ = 55862531712. Its totient is φ = 7198293760.

The previous prime is 21609543493. The next prime is 21609543521. The reversal of 21609543504 is 40534590612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80904 + ... + 223079.

Almost surely, 2^21609543504 is an apocalyptic number.

21609543504 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21609543504 is an abundant number, since it is smaller than the sum of its proper divisors (34252988208).

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

21609543504 is a wasteful number, since it uses less digits than its factorization.

21609543504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305475 (or 305469 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 39.

The spelling of 21609543504 in words is "twenty-one billion, six hundred nine million, five hundred forty-three thousand, five hundred four".