21022988 has 24 divisors (see below), whose sum is σ = 42276864. Its totient is φ = 8960400.

The previous prime is 21022921. The next prime is 21022997. The reversal of 21022988 is 88922012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3383 + ... + 7313.

It is an arithmetic number, because the mean of its divisors is an integer number (1761536).

Almost surely, 2^21022988 is an apocalyptic number.

21022988 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21022988 is an abundant number, since it is smaller than the sum of its proper divisors (21253876).

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

21022988 is a wasteful number, since it uses less digits than its factorization.

21022988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4133 (or 4131 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 21022988 is about 4585.0832053519. The cubic root of 21022988 is about 275.9930510048.

The spelling of 21022988 in words is "twenty-one million, twenty-two thousand, nine hundred eighty-eight".