391656901 has 2 divisors, whose sum is σ = 391656902. Its totient is φ = 391656900.

The previous prime is 391656893. The next prime is 391656911. The reversal of 391656901 is 109656193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 385179876 + 6477025 = 19626^2 + 2545^2 .

It is an emirp because it is prime and its reverse (109656193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 391656901 - 2³ = 391656893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391656911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195828450 + 195828451.

It is an arithmetic number, because the mean of its divisors is an integer number (195828451).

Almost surely, 2^391656901 is an apocalyptic number.

It is an amenable number.

391656901 is a deficient number, since it is larger than the sum of its proper divisors (1).

391656901 is an equidigital number, since it uses as much as digits as its factorization.

391656901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43740, while the sum is 40.

The square root of 391656901 is about 19790.3234182769. The cubic root of 391656901 is about 731.6475585688.

The spelling of 391656901 in words is "three hundred ninety-one million, six hundred fifty-six thousand, nine hundred one".