18121572 has 54 divisors (see below), whose sum is σ = 53291238. Its totient is φ = 5177088.

The previous prime is 18121567. The next prime is 18121583. The reversal of 18121572 is 27512181.

It can be written as a sum of positive squares in only one way, i.e., 13351716 + 4769856 = 3654^2 + 2184^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3373 + ... + 6900.

Almost surely, 2^18121572 is an apocalyptic number.

18121572 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18121572 is an abundant number, since it is smaller than the sum of its proper divisors (35169666).

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

18121572 is a wasteful number, since it uses less digits than its factorization.

18121572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10297 (or 10285 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 18121572 is about 4256.9439742613. The cubic root of 18121572 is about 262.6628323054.

The spelling of 18121572 in words is "eighteen million, one hundred twenty-one thousand, five hundred seventy-two".