21489590 has 32 divisors (see below), whose sum is σ = 40637376. Its totient is φ = 8166400.

The previous prime is 21489583. The next prime is 21489599. The reversal of 21489590 is 9598412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21489599) 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, 53390 + ... + 53790.

It is an arithmetic number, because the mean of its divisors is an integer number (1269918).

Almost surely, 2^21489590 is an apocalyptic number.

21489590 is a deficient number, since it is larger than the sum of its proper divisors (19147786).

21489590 is a wasteful number, since it uses less digits than its factorization.

21489590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 21489590 is about 4635.6865726664. The cubic root of 21489590 is about 278.0200027013.

The spelling of 21489590 in words is "twenty-one million, four hundred eighty-nine thousand, five hundred ninety".