391512493 has 2 divisors, whose sum is σ = 391512494. Its totient is φ = 391512492.

The previous prime is 391512469. The next prime is 391512497. The reversal of 391512493 is 394215193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 308283364 + 83229129 = 17558^2 + 9123^2 .

It is a cyclic number.

It is not a de Polignac number, because 391512493 - 2²⁵ = 357958061 is a prime.

It is equal to p_20907586 and since 391512493 and 20907586 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391512497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195756246 + 195756247.

It is an arithmetic number, because the mean of its divisors is an integer number (195756247).

Almost surely, 2^391512493 is an apocalyptic number.

It is an amenable number.

391512493 is a deficient number, since it is larger than the sum of its proper divisors (1).

391512493 is an equidigital number, since it uses as much as digits as its factorization.

391512493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29160, while the sum is 37.

The square root of 391512493 is about 19786.6746321862. The cubic root of 391512493 is about 731.5576254764.

The spelling of 391512493 in words is "three hundred ninety-one million, five hundred twelve thousand, four hundred ninety-three".