1391393257 has 12 divisors (see below), whose sum is σ = 1457026704. Its totient is φ = 1328604200.

The previous prime is 1391393249. The next prime is 1391393279. The reversal of 1391393257 is 7523931931.

It is not a de Polignac number, because 1391393257 - 2³ = 1391393249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1391393207) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 359382 + ... + 363232.

It is an arithmetic number, because the mean of its divisors is an integer number (121418892).

Almost surely, 2^1391393257 is an apocalyptic number.

It is an amenable number.

1391393257 is a deficient number, since it is larger than the sum of its proper divisors (65633447).

1391393257 is an equidigital number, since it uses as much as digits as its factorization.

1391393257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4580 (or 4557 counting only the distinct ones).

The product of its digits is 153090, while the sum is 43.

The square root of 1391393257 is about 37301.3841164105. The cubic root of 1391393257 is about 1116.3917834221.

The spelling of 1391393257 in words is "one billion, three hundred ninety-one million, three hundred ninety-three thousand, two hundred fifty-seven".