21282990 has 16 divisors (see below), whose sum is σ = 51079248. Its totient is φ = 5675456.

The previous prime is 21282971. The next prime is 21282991. The reversal of 21282990 is 9928212.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21282991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 354687 + ... + 354746.

It is an arithmetic number, because the mean of its divisors is an integer number (3192453).

Almost surely, 2^21282990 is an apocalyptic number.

21282990 is an abundant number, since it is smaller than the sum of its proper divisors (29796258).

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

21282990 is a wasteful number, since it uses less digits than its factorization.

21282990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 709443.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21282990 is about 4613.3491088362. The cubic root of 21282990 is about 277.1261746686.

The spelling of 21282990 in words is "twenty-one million, two hundred eighty-two thousand, nine hundred ninety".