21907490 has 32 divisors (see below), whose sum is σ = 43580160. Its totient is φ = 7862400.

The previous prime is 21907471. The next prime is 21907493. The reversal of 21907490 is 9470912.

It is not an unprimeable number, because it can be changed into a prime (21907493) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7430 + ... + 9950.

It is an arithmetic number, because the mean of its divisors is an integer number (1361880).

Almost surely, 2^21907490 is an apocalyptic number.

21907490 is a deficient number, since it is larger than the sum of its proper divisors (21672670).

21907490 is a wasteful number, since it uses less digits than its factorization.

21907490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2618.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 21907490 is about 4680.5437718282. The cubic root of 21907490 is about 279.8106287549.

The spelling of 21907490 in words is "twenty-one million, nine hundred seven thousand, four hundred ninety".