21640178360 has 32 divisors (see below), whose sum is σ = 50807377440. Its totient is φ = 8279720064.

The previous prime is 21640178359. The next prime is 21640178377. The reversal of 21640178360 is 6387104612.

It is a super-2 number, since 2×21640178360² (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, 11760047 + ... + 11761886.

It is an arithmetic number, because the mean of its divisors is an integer number (1587730545).

Almost surely, 2^21640178360 is an apocalyptic number.

21640178360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21640178360 is an abundant number, since it is smaller than the sum of its proper divisors (29167199080).

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

21640178360 is a wasteful number, since it uses less digits than its factorization.

21640178360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23521967 (or 23521963 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 38.

The spelling of 21640178360 in words is "twenty-one billion, six hundred forty million, one hundred seventy-eight thousand, three hundred sixty".