11638691978 has 8 divisors (see below), whose sum is σ = 18217083168. Its totient is φ = 5566330924.

The previous prime is 11638691959. The next prime is 11638691993. The reversal of 11638691978 is 87919683611.

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

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, 126507476 + ... + 126507567.

It is an arithmetic number, because the mean of its divisors is an integer number (2277135396).

Almost surely, 2^11638691978 is an apocalyptic number.

11638691978 is a deficient number, since it is larger than the sum of its proper divisors (6578391190).

11638691978 is a wasteful number, since it uses less digits than its factorization.

11638691978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253015068.

The product of its digits is 3919104, while the sum is 59.

The spelling of 11638691978 in words is "eleven billion, six hundred thirty-eight million, six hundred ninety-one thousand, nine hundred seventy-eight".