21604568316 has 24 divisors (see below), whose sum is σ = 51265079040. Its totient is φ = 7079462832.

The previous prime is 21604568233. The next prime is 21604568333. The reversal of 21604568316 is 61386540612.

It is a super-2 number, since 2×21604568316² (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 7 ways as a sum of consecutive naturals, for example, 15256756 + ... + 15258171.

It is an arithmetic number, because the mean of its divisors is an integer number (2136044960).

Almost surely, 2^21604568316 is an apocalyptic number.

It is an amenable number.

21604568316 is an abundant number, since it is smaller than the sum of its proper divisors (29660510724).

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

21604568316 is a wasteful number, since it uses less digits than its factorization.

21604568316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30514993 (or 30514991 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 21604568316 in words is "twenty-one billion, six hundred four million, five hundred sixty-eight thousand, three hundred sixteen".