391000157 has 4 divisors (see below), whose sum is σ = 391054236. Its totient is φ = 390946080.

The previous prime is 391000147. The next prime is 391000177. The reversal of 391000157 is 751000193.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 111809476 + 279190681 = 10574^2 + 16709^2 .

It is a cyclic number.

It is not a de Polignac number, because 391000157 - 2⁸ = 390999901 is a prime.

It is a super-2 number, since 2×391000157² = 305762245548049298, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391000147) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14144 + ... + 31337.

It is an arithmetic number, because the mean of its divisors is an integer number (97763559).

Almost surely, 2^391000157 is an apocalyptic number.

It is an amenable number.

391000157 is a deficient number, since it is larger than the sum of its proper divisors (54079).

391000157 is an equidigital number, since it uses as much as digits as its factorization.

391000157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54078.

The product of its (nonzero) digits is 945, while the sum is 26.

The square root of 391000157 is about 19773.7239032004. The cubic root of 391000157 is about 731.2383790298.

The spelling of 391000157 in words is "three hundred ninety-one million, one hundred fifty-seven", and thus it is an aban number.