18915968 has 32 divisors (see below), whose sum is σ = 39905460. Its totient is φ = 8900608.

The previous prime is 18915961. The next prime is 18915973. The reversal of 18915968 is 86951981.

It can be written as a sum of positive squares in 2 ways, for example, as 18593344 + 322624 = 4312^2 + 568^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (18915961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2171 + ... + 6522.

Almost surely, 2^18915968 is an apocalyptic number.

It is an amenable number.

18915968 is an abundant number, since it is smaller than the sum of its proper divisors (20989492).

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

18915968 is an equidigital number, since it uses as much as digits as its factorization.

18915968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8724 (or 8712 counting only the distinct ones).

The product of its digits is 155520, while the sum is 47.

The square root of 18915968 is about 4349.2491305971. The cubic root of 18915968 is about 266.4461955498.

The spelling of 18915968 in words is "eighteen million, nine hundred fifteen thousand, nine hundred sixty-eight".