391949513 has 2 divisors, whose sum is σ = 391949514. Its totient is φ = 391949512.

The previous prime is 391949507. The next prime is 391949521. The reversal of 391949513 is 315949193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 218684944 + 173264569 = 14788^2 + 13163^2 .

It is a cyclic number.

It is not a de Polignac number, because 391949513 - 2¹⁰ = 391948489 is a prime.

It is not a weakly prime, because it can be changed into another prime (391949533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195974756 + 195974757.

It is an arithmetic number, because the mean of its divisors is an integer number (195974757).

Almost surely, 2^391949513 is an apocalyptic number.

It is an amenable number.

391949513 is a deficient number, since it is larger than the sum of its proper divisors (1).

391949513 is an equidigital number, since it uses as much as digits as its factorization.

391949513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 131220, while the sum is 44.

The square root of 391949513 is about 19797.7148428802. The cubic root of 391949513 is about 731.8297210353.

The spelling of 391949513 in words is "three hundred ninety-one million, nine hundred forty-nine thousand, five hundred thirteen".