21130661560 has 64 divisors (see below), whose sum is σ = 47954760480. Its totient is φ = 8379371520.

The previous prime is 21130661551. The next prime is 21130661593. The reversal of 21130661560 is 6516603112.

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, 9813444 + ... + 9815596.

Almost surely, 2^21130661560 is an apocalyptic number.

21130661560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21130661560 is an abundant number, since it is smaller than the sum of its proper divisors (26824098920).

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

21130661560 is a wasteful number, since it uses less digits than its factorization.

21130661560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4168 (or 4164 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The spelling of 21130661560 in words is "twenty-one billion, one hundred thirty million, six hundred sixty-one thousand, five hundred sixty".