18978955 has 8 divisors (see below), whose sum is σ = 22798512. Its totient is φ = 15167328.

The previous prime is 18978917. The next prime is 18978959. The reversal of 18978955 is 55987981.

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

It is a cyclic number.

It is not a de Polignac number, because 18978955 - 2²³ = 10590347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18978959) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6969 + ... + 9301.

It is an arithmetic number, because the mean of its divisors is an integer number (2849814).

Almost surely, 2^18978955 is an apocalyptic number.

18978955 is a deficient number, since it is larger than the sum of its proper divisors (3819557).

18978955 is a wasteful number, since it uses less digits than its factorization.

18978955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3965.

The product of its digits is 907200, while the sum is 52.

The square root of 18978955 is about 4356.4842476474. The cubic root of 18978955 is about 266.7416082774.

The spelling of 18978955 in words is "eighteen million, nine hundred seventy-eight thousand, nine hundred fifty-five".