21492990 has 48 divisors (see below), whose sum is σ = 58827600. Its totient is φ = 5429376.

The previous prime is 21492953. The next prime is 21493007. The reversal of 21492990 is 9929412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4575 + ... + 7994.

It is an arithmetic number, because the mean of its divisors is an integer number (1225575).

Almost surely, 2^21492990 is an apocalyptic number.

21492990 is an abundant number, since it is smaller than the sum of its proper divisors (37334610).

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

21492990 is a wasteful number, since it uses less digits than its factorization.

21492990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12601 (or 12598 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 21492990 is about 4636.0532783824. The cubic root of 21492990 is about 278.0346643454.

The spelling of 21492990 in words is "twenty-one million, four hundred ninety-two thousand, nine hundred ninety".