21512680 has 32 divisors (see below), whose sum is σ = 55319040. Its totient is φ = 7375680.

The previous prime is 21512669. The next prime is 21512713. The reversal of 21512680 is 8621512.

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, 38136 + ... + 38695.

It is an arithmetic number, because the mean of its divisors is an integer number (1728720).

Almost surely, 2^21512680 is an apocalyptic number.

21512680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21512680 is an abundant number, since it is smaller than the sum of its proper divisors (33806360).

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

21512680 is a wasteful number, since it uses less digits than its factorization.

21512680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76849 (or 76845 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 21512680 is about 4638.1763657714. The cubic root of 21512680 is about 278.1195421224.

The spelling of 21512680 in words is "twenty-one million, five hundred twelve thousand, six hundred eighty".