18531572 has 6 divisors (see below), whose sum is σ = 32430258. Its totient is φ = 9265784.

The previous prime is 18531553. The next prime is 18531589. The reversal of 18531572 is 27513581.

It can be written as a sum of positive squares in only one way, i.e., 11792356 + 6739216 = 3434^2 + 2596^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2316443 + ... + 2316450.

It is an arithmetic number, because the mean of its divisors is an integer number (5405043).

Almost surely, 2^18531572 is an apocalyptic number.

It is an amenable number.

18531572 is a deficient number, since it is larger than the sum of its proper divisors (13898686).

18531572 is a wasteful number, since it uses less digits than its factorization.

18531572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4632897 (or 4632895 counting only the distinct ones).

The product of its digits is 8400, while the sum is 32.

The square root of 18531572 is about 4304.8312394332. The cubic root of 18531572 is about 264.6289907251.

Subtracting 18531572 from its reverse (27513581), we obtain a square (8982009 = 2997²).

The spelling of 18531572 in words is "eighteen million, five hundred thirty-one thousand, five hundred seventy-two".