11999939978 has 48 divisors (see below), whose sum is σ = 20158085376. Its totient is φ = 5349576960.

The previous prime is 11999939977. The next prime is 11999939981. The reversal of 11999939978 is 87993999911.

It is not an unprimeable number, because it can be changed into a prime (11999939977) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9251426 + ... + 9252722.

It is an arithmetic number, because the mean of its divisors is an integer number (419960112).

Almost surely, 2^11999939978 is an apocalyptic number.

11999939978 is a deficient number, since it is larger than the sum of its proper divisors (8158145398).

11999939978 is a wasteful number, since it uses less digits than its factorization.

11999939978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2239 (or 2226 counting only the distinct ones).

The product of its digits is 89282088, while the sum is 74.

The spelling of 11999939978 in words is "eleven billion, nine hundred ninety-nine million, nine hundred thirty-nine thousand, nine hundred seventy-eight".