21866988 has 48 divisors (see below), whose sum is σ = 59947776. Its totient is φ = 6116160.

The previous prime is 21866941. The next prime is 21866989. The reversal of 21866988 is 88966812.

It is not an unprimeable number, because it can be changed into a prime (21866989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4656 + ... + 8087.

It is an arithmetic number, because the mean of its divisors is an integer number (1248912).

Almost surely, 2^21866988 is an apocalyptic number.

It is an amenable number.

21866988 is an abundant number, since it is smaller than the sum of its proper divisors (38080788).

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

21866988 is a wasteful number, since it uses less digits than its factorization.

21866988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12774 (or 12772 counting only the distinct ones).

The product of its digits is 331776, while the sum is 48.

The square root of 21866988 is about 4676.2151361972. The cubic root of 21866988 is about 279.6380868335.

The spelling of 21866988 in words is "twenty-one million, eight hundred sixty-six thousand, nine hundred eighty-eight".