21132990 has 24 divisors (see below), whose sum is σ = 54946008. Its totient is φ = 5635440.

The previous prime is 21132983. The next prime is 21133003. The reversal of 21132990 is 9923112.

It is a congruent number.

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, 117316 + ... + 117495.

It is an arithmetic number, because the mean of its divisors is an integer number (2289417).

Almost surely, 2^21132990 is an apocalyptic number.

21132990 is an abundant number, since it is smaller than the sum of its proper divisors (33813018).

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

21132990 is a wasteful number, since it uses less digits than its factorization.

21132990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234824 (or 234821 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 21132990 is about 4597.0631929526. The cubic root of 21132990 is about 276.4735882915.

It can be divided in two parts, 21132 and 990, that added together give a palindrome (22122).

The spelling of 21132990 in words is "twenty-one million, one hundred thirty-two thousand, nine hundred ninety".