391318157 has 2 divisors, whose sum is σ = 391318158. Its totient is φ = 391318156.

The previous prime is 391318139. The next prime is 391318163. The reversal of 391318157 is 751813193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 342472036 + 48846121 = 18506^2 + 6989^2 .

It is a cyclic number.

It is not a de Polignac number, because 391318157 - 2⁶ = 391318093 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 391318157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391318117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195659078 + 195659079.

It is an arithmetic number, because the mean of its divisors is an integer number (195659079).

Almost surely, 2^391318157 is an apocalyptic number.

It is an amenable number.

391318157 is a deficient number, since it is larger than the sum of its proper divisors (1).

391318157 is an equidigital number, since it uses as much as digits as its factorization.

391318157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 38.

The square root of 391318157 is about 19781.7632429468. The cubic root of 391318157 is about 731.4365637696.

The spelling of 391318157 in words is "three hundred ninety-one million, three hundred eighteen thousand, one hundred fifty-seven".