21276880 has 20 divisors (see below), whose sum is σ = 49468932. Its totient is φ = 8510720.

The previous prime is 21276859. The next prime is 21276907. The reversal of 21276880 is 8867212.

It can be written as a sum of positive squares in 2 ways, for example, as 5973136 + 15303744 = 2444^2 + 3912^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132901 + ... + 133060.

Almost surely, 2^21276880 is an apocalyptic number.

21276880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21276880 is an abundant number, since it is smaller than the sum of its proper divisors (28192052).

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

21276880 is a wasteful number, since it uses less digits than its factorization.

21276880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265974 (or 265968 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 21276880 is about 4612.6868525839. The cubic root of 21276880 is about 277.0996526591.

The spelling of 21276880 in words is "twenty-one million, two hundred seventy-six thousand, eight hundred eighty".