18909472 has 12 divisors (see below), whose sum is σ = 37228086. Its totient is φ = 9454720.

The previous prime is 18909469. The next prime is 18909493. The reversal of 18909472 is 27490981.

It can be written as a sum of positive squares in only one way, i.e., 11532816 + 7376656 = 3396^2 + 2716^2 .

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 295429 + ... + 295492.

Almost surely, 2^18909472 is an apocalyptic number.

It is an amenable number.

18909472 is a deficient number, since it is larger than the sum of its proper divisors (18318614).

18909472 is an equidigital number, since it uses as much as digits as its factorization.

18909472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590931 (or 590923 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 18909472 is about 4348.5022708974. The cubic root of 18909472 is about 266.4156916451.

The spelling of 18909472 in words is "eighteen million, nine hundred nine thousand, four hundred seventy-two".