318978991 has 2 divisors, whose sum is σ = 318978992. Its totient is φ = 318978990.

The previous prime is 318978983. The next prime is 318979009. The reversal of 318978991 is 199879813.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 318978991 - 2³ = 318978983 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (318978911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159489495 + 159489496.

It is an arithmetic number, because the mean of its divisors is an integer number (159489496).

Almost surely, 2^318978991 is an apocalyptic number.

318978991 is a deficient number, since it is larger than the sum of its proper divisors (1).

318978991 is an equidigital number, since it uses as much as digits as its factorization.

318978991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 55.

The square root of 318978991 is about 17859.9829507197. The cubic root of 318978991 is about 683.2621449272.

The spelling of 318978991 in words is "three hundred eighteen million, nine hundred seventy-eight thousand, nine hundred ninety-one".