18001972 has 6 divisors (see below), whose sum is σ = 31503458. Its totient is φ = 9000984.

The previous prime is 18001969. The next prime is 18001981. The reversal of 18001972 is 27910081.

It can be written as a sum of positive squares in only one way, i.e., 17355556 + 646416 = 4166^2 + 804^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18001972.

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, 2250243 + ... + 2250250.

Almost surely, 2^18001972 is an apocalyptic number.

It is an amenable number.

18001972 is a deficient number, since it is larger than the sum of its proper divisors (13501486).

18001972 is a wasteful number, since it uses less digits than its factorization.

18001972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4500497 (or 4500495 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 18001972 is about 4242.8730831831. The cubic root of 18001972 is about 262.0837096307.

The spelling of 18001972 in words is "eighteen million, one thousand, nine hundred seventy-two".