21977900 has 36 divisors (see below), whose sum is σ = 54506928. Its totient is φ = 7535040.

The previous prime is 21977897. The next prime is 21977929. The reversal of 21977900 is 977912.

It is a Harshad number since it is a multiple of its sum of digits (35).

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, 14999 + ... + 16398.

Almost surely, 2^21977900 is an apocalyptic number.

21977900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21977900 is an abundant number, since it is smaller than the sum of its proper divisors (32529028).

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

21977900 is a wasteful number, since it uses less digits than its factorization.

21977900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31418 (or 31411 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 35.

The square root of 21977900 is about 4688.0592999662. The cubic root of 21977900 is about 280.1100757681.

The spelling of 21977900 in words is "twenty-one million, nine hundred seventy-seven thousand, nine hundred".