18520978 has 8 divisors (see below), whose sum is σ = 31750272. Its totient is φ = 7937556.

The previous prime is 18520969. The next prime is 18520993. The reversal of 18520978 is 87902581.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 18520978.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 661450 + ... + 661477.

It is an arithmetic number, because the mean of its divisors is an integer number (3968784).

Almost surely, 2^18520978 is an apocalyptic number.

18520978 is a deficient number, since it is larger than the sum of its proper divisors (13229294).

18520978 is a wasteful number, since it uses less digits than its factorization.

18520978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1322936.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 18520978 is about 4303.6005855562. The cubic root of 18520978 is about 264.5785540267.

The spelling of 18520978 in words is "eighteen million, five hundred twenty thousand, nine hundred seventy-eight".