18989972 has 6 divisors (see below), whose sum is σ = 33232458. Its totient is φ = 9494984.

The previous prime is 18989959. The next prime is 18990017. The reversal of 18989972 is 27998981.

It can be written as a sum of positive squares in only one way, i.e., 12859396 + 6130576 = 3586^2 + 2476^2 .

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, 2373743 + ... + 2373750.

It is an arithmetic number, because the mean of its divisors is an integer number (5538743).

Almost surely, 2^18989972 is an apocalyptic number.

It is an amenable number.

18989972 is a deficient number, since it is larger than the sum of its proper divisors (14242486).

18989972 is a wasteful number, since it uses less digits than its factorization.

18989972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4747497 (or 4747495 counting only the distinct ones).

The product of its digits is 653184, while the sum is 53.

The square root of 18989972 is about 4357.7485012332. The cubic root of 18989972 is about 266.7932114673.

Subtracting 18989972 from its reverse (27998981), we obtain a palindrome (9009009).

The spelling of 18989972 in words is "eighteen million, nine hundred eighty-nine thousand, nine hundred seventy-two".