21321604540 has 48 divisors (see below), whose sum is σ = 45161091360. Its totient is φ = 8455299840.

The previous prime is 21321604441. The next prime is 21321604583. The reversal of 21321604540 is 4540612312.

It is a super-2 number, since 2×21321604540² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21321604499 and 21321604508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3174706 + ... + 3181414.

It is an arithmetic number, because the mean of its divisors is an integer number (940856070).

Almost surely, 2^21321604540 is an apocalyptic number.

21321604540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21321604540 is an abundant number, since it is smaller than the sum of its proper divisors (23839486820).

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

21321604540 is a wasteful number, since it uses less digits than its factorization.

21321604540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8062 (or 8060 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The spelling of 21321604540 in words is "twenty-one billion, three hundred twenty-one million, six hundred four thousand, five hundred forty".