18812978 has 6 divisors (see below), whose sum is σ = 28228671. Its totient is φ = 9403422.

The previous prime is 18812953. The next prime is 18812987. The reversal of 18812978 is 87921881.

It can be written as a sum of positive squares in only one way, i.e., 9406489 + 9406489 = 3067^2 + 3067^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3067.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4601 + ... + 7667.

Almost surely, 2^18812978 is an apocalyptic number.

18812978 is a deficient number, since it is larger than the sum of its proper divisors (9415693).

18812978 is an frugal number, since it uses more digits than its factorization.

18812978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6136 (or 3069 counting only the distinct ones).

The product of its digits is 64512, while the sum is 44.

The square root of 18812978 is about 4337.3929957983. The cubic root of 18812978 is about 265.9617503936.

The spelling of 18812978 in words is "eighteen million, eight hundred twelve thousand, nine hundred seventy-eight".