18972320 has 48 divisors (see below), whose sum is σ = 45087840. Its totient is φ = 7544064.

The previous prime is 18972313. The next prime is 18972353. The reversal of 18972320 is 2327981.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45071 + ... + 45489.

It is an arithmetic number, because the mean of its divisors is an integer number (939330).

Almost surely, 2^18972320 is an apocalyptic number.

18972320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18972320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22543920).

18972320 is an abundant number, since it is smaller than the sum of its proper divisors (26115520).

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

18972320 is a wasteful number, since it uses less digits than its factorization.

18972320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717 (or 709 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 18972320 is about 4355.7226725309. The cubic root of 18972320 is about 266.7105205655.

The spelling of 18972320 in words is "eighteen million, nine hundred seventy-two thousand, three hundred twenty".