391615493 has 2 divisors, whose sum is σ = 391615494. Its totient is φ = 391615492.

The previous prime is 391615447. The next prime is 391615537. The reversal of 391615493 is 394516193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 367182244 + 24433249 = 19162^2 + 4943^2 .

It is an emirp because it is prime and its reverse (394516193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 391615493 - 2¹² = 391611397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 391615493.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391615423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195807746 + 195807747.

It is an arithmetic number, because the mean of its divisors is an integer number (195807747).

Almost surely, 2^391615493 is an apocalyptic number.

It is an amenable number.

391615493 is a deficient number, since it is larger than the sum of its proper divisors (1).

391615493 is an equidigital number, since it uses as much as digits as its factorization.

391615493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 87480, while the sum is 41.

The square root of 391615493 is about 19789.2772227790. The cubic root of 391615493 is about 731.6217731345.

The spelling of 391615493 in words is "three hundred ninety-one million, six hundred fifteen thousand, four hundred ninety-three".