691431227 has 2 divisors, whose sum is σ = 691431228. Its totient is φ = 691431226.

The previous prime is 691431211. The next prime is 691431263. The reversal of 691431227 is 722134196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691431227 - 2⁴ = 691431211 is a prime.

It is not a weakly prime, because it can be changed into another prime (691431277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345715613 + 345715614.

It is an arithmetic number, because the mean of its divisors is an integer number (345715614).

Almost surely, 2^691431227 is an apocalyptic number.

691431227 is a deficient number, since it is larger than the sum of its proper divisors (1).

691431227 is an equidigital number, since it uses as much as digits as its factorization.

691431227 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 35.

The square root of 691431227 is about 26295.0799010005. The cubic root of 691431227 is about 884.2661421482.

The spelling of 691431227 in words is "six hundred ninety-one million, four hundred thirty-one thousand, two hundred twenty-seven".