18099972 has 36 divisors (see below), whose sum is σ = 49913136. Its totient is φ = 5484720.

The previous prime is 18099971. The next prime is 18099997. The reversal of 18099972 is 27999081.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (18099971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22458 + ... + 23249.

It is an arithmetic number, because the mean of its divisors is an integer number (1386476).

Almost surely, 2^18099972 is an apocalyptic number.

18099972 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18099972 is an abundant number, since it is smaller than the sum of its proper divisors (31813164).

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

18099972 is a wasteful number, since it uses less digits than its factorization.

18099972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45728 (or 45723 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 18099972 is about 4254.4061865318. The cubic root of 18099972 is about 262.5584305303.

It can be divided in two parts, 1809 and 9972, that added together give a triangular number (11781 = T₁₅₃).

The spelling of 18099972 in words is "eighteen million, ninety-nine thousand, nine hundred seventy-two".