21122880 has 56 divisors (see below), whose sum is σ = 67068192. Its totient is φ = 5632512.

The previous prime is 21122869. The next prime is 21122887. The reversal of 21122880 is 8822112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21122880.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10042 + ... + 11961.

Almost surely, 2^21122880 is an apocalyptic number.

21122880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21122880 is an abundant number, since it is smaller than the sum of its proper divisors (45945312).

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

21122880 is a wasteful number, since it uses less digits than its factorization.

21122880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22023 (or 22013 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 21122880 is about 4595.9634463298. The cubic root of 21122880 is about 276.4294930353.

Adding to 21122880 its reverse (8822112), we get a palindrome (29944992).

The spelling of 21122880 in words is "twenty-one million, one hundred twenty-two thousand, eight hundred eighty".