21107980 has 12 divisors (see below), whose sum is σ = 44326800. Its totient is φ = 8443184.

The previous prime is 21107953. The next prime is 21107981. The reversal of 21107980 is 8970112.

It is not an unprimeable number, because it can be changed into a prime (21107981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 527680 + ... + 527719.

It is an arithmetic number, because the mean of its divisors is an integer number (3693900).

Almost surely, 2^21107980 is an apocalyptic number.

21107980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21107980 is an abundant number, since it is smaller than the sum of its proper divisors (23218820).

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

21107980 is a wasteful number, since it uses less digits than its factorization.

21107980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055408 (or 1055406 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 21107980 is about 4594.3421727164. The cubic root of 21107980 is about 276.3644803052.

The spelling of 21107980 in words is "twenty-one million, one hundred seven thousand, nine hundred eighty".