21621628680 has 64 divisors (see below), whose sum is σ = 64918022400. Its totient is φ = 5761044480.

The previous prime is 21621628673. The next prime is 21621628729. The reversal of 21621628680 is 8682612612.

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, 74536 + ... + 220904.

It is an arithmetic number, because the mean of its divisors is an integer number (1014344100).

Almost surely, 2^21621628680 is an apocalyptic number.

21621628680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21621628680 is an abundant number, since it is smaller than the sum of its proper divisors (43296393720).

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

21621628680 is a wasteful number, since it uses less digits than its factorization.

21621628680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147614 (or 147610 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 42.

The spelling of 21621628680 in words is "twenty-one billion, six hundred twenty-one million, six hundred twenty-eight thousand, six hundred eighty".