18979630778 has 16 divisors (see below), whose sum is σ = 29243876904. Its totient is φ = 9231759360.

The previous prime is 18979630729. The next prime is 18979630781. The reversal of 18979630778 is 87703697981.

It can be written as a sum of positive squares in 4 ways, for example, as 11350132369 + 7629498409 = 106537^2 + 87347^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 497918 + ... + 534678.

Almost surely, 2^18979630778 is an apocalyptic number.

18979630778 is a deficient number, since it is larger than the sum of its proper divisors (10264246126).

18979630778 is a wasteful number, since it uses less digits than its factorization.

18979630778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43777.

The product of its (nonzero) digits is 32006016, while the sum is 65.

The spelling of 18979630778 in words is "eighteen billion, nine hundred seventy-nine million, six hundred thirty thousand, seven hundred seventy-eight".