391397 has 2 divisors, whose sum is σ = 391398. Its totient is φ = 391396.

The previous prime is 391393. The next prime is 391399. The reversal of 391397 is 793193.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 279841 + 111556 = 529^2 + 334^2 .

It is a cyclic number.

It is not a de Polignac number, because 391397 - 2² = 391393 is a prime.

It is a super-2 number, since 2×391397² = 306383223218, which contains 22 as substring.

Together with 391399, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 391397.

It is not a weakly prime, because it can be changed into another prime (391393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195698 + 195699.

It is an arithmetic number, because the mean of its divisors is an integer number (195699).

2³⁹¹³⁹⁷ is an apocalyptic number.

It is an amenable number.

391397 is a deficient number, since it is larger than the sum of its proper divisors (1).

391397 is an equidigital number, since it uses as much as digits as its factorization.

391397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5103, while the sum is 32.

The square root of 391397 is about 625.6172951574. The cubic root of 391397 is about 73.1485683886.

The spelling of 391397 in words is "three hundred ninety-one thousand, three hundred ninety-seven".