21472990 has 64 divisors (see below), whose sum is σ = 48936960. Its totient is φ = 6589440.

The previous prime is 21472973. The next prime is 21472993. The reversal of 21472990 is 9927412.

It is a happy number.

It is a super-2 number, since 2×21472990² = 922178599080200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21472993) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60654 + ... + 61006.

It is an arithmetic number, because the mean of its divisors is an integer number (764640).

Almost surely, 2^21472990 is an apocalyptic number.

21472990 is an abundant number, since it is smaller than the sum of its proper divisors (27463970).

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

21472990 is a wasteful number, since it uses less digits than its factorization.

21472990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 21472990 is about 4633.8957692205. The cubic root of 21472990 is about 277.9483971642.

The spelling of 21472990 in words is "twenty-one million, four hundred seventy-two thousand, nine hundred ninety".