691431263 has 2 divisors, whose sum is σ = 691431264. Its totient is φ = 691431262.

The previous prime is 691431227. The next prime is 691431277. The reversal of 691431263 is 362134196.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691431263 - 2⁸ = 691431007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691431203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345715631 + 345715632.

It is an arithmetic number, because the mean of its divisors is an integer number (345715632).

Almost surely, 2^691431263 is an apocalyptic number.

691431263 is a deficient number, since it is larger than the sum of its proper divisors (1).

691431263 is an equidigital number, since it uses as much as digits as its factorization.

691431263 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 35.

The square root of 691431263 is about 26295.0805855392. The cubic root of 691431263 is about 884.2661574949.

The spelling of 691431263 in words is "six hundred ninety-one million, four hundred thirty-one thousand, two hundred sixty-three".