21557011560 has 64 divisors (see below), whose sum is σ = 73909756800. Its totient is φ = 4927316736.

The previous prime is 21557011559. The next prime is 21557011631. The reversal of 21557011560 is 6511075512.

It is a happy 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, 12830715 + ... + 12832394.

It is an arithmetic number, because the mean of its divisors is an integer number (1154839950).

Almost surely, 2^21557011560 is an apocalyptic number.

21557011560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21557011560 is an abundant number, since it is smaller than the sum of its proper divisors (52352745240).

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

21557011560 is a wasteful number, since it uses less digits than its factorization.

21557011560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25663130 (or 25663126 counting only the distinct ones).

The product of its (nonzero) digits is 10500, while the sum is 33.

The spelling of 21557011560 in words is "twenty-one billion, five hundred fifty-seven million, eleven thousand, five hundred sixty".