231993978 has 16 divisors (see below), whose sum is σ = 464641920. Its totient is φ = 77222336.

The previous prime is 231993941. The next prime is 231994051. The reversal of 231993978 is 879399132.

It is a happy number.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 231993978.

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, 22575 + ... + 31202.

It is an arithmetic number, because the mean of its divisors is an integer number (29040120).

Almost surely, 2^231993978 is an apocalyptic number.

231993978 is an abundant number, since it is smaller than the sum of its proper divisors (232647942).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231993978 is a wasteful number, since it uses less digits than its factorization.

231993978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54501.

The product of its digits is 734832, while the sum is 51.

The square root of 231993978 is about 15231.3485286103. The cubic root of 231993978 is about 614.4580485705.

The spelling of 231993978 in words is "two hundred thirty-one million, nine hundred ninety-three thousand, nine hundred seventy-eight".