21512880 has 60 divisors (see below), whose sum is σ = 72249840. Its totient is φ = 5736576.

The previous prime is 21512861. The next prime is 21512893. The reversal of 21512880 is 8821512.

It is a tau number, because it is divible by the number of its divisors (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14220 + ... + 15659.

It is an arithmetic number, because the mean of its divisors is an integer number (1204164).

Almost surely, 2^21512880 is an apocalyptic number.

21512880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21512880 is an abundant number, since it is smaller than the sum of its proper divisors (50736960).

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

21512880 is a wasteful number, since it uses less digits than its factorization.

21512880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29898 (or 29889 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 21512880 is about 4638.1979259191. The cubic root of 21512880 is about 278.1204039976.

The spelling of 21512880 in words is "twenty-one million, five hundred twelve thousand, eight hundred eighty".