1264431691 has 2 divisors, whose sum is σ = 1264431692. Its totient is φ = 1264431690.

The previous prime is 1264431683. The next prime is 1264431757. The reversal of 1264431691 is 1961344621.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1264431691 - 2³ = 1264431683 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1264431691.

It is not a weakly prime, because it can be changed into another prime (1264431671) 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, 632215845 + 632215846.

It is an arithmetic number, because the mean of its divisors is an integer number (632215846).

Almost surely, 2^1264431691 is an apocalyptic number.

1264431691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1264431691 is an equidigital number, since it uses as much as digits as its factorization.

1264431691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 37.

The square root of 1264431691 is about 35558.8482799992. The cubic root of 1264431691 is about 1081.3471104556.

The spelling of 1264431691 in words is "one billion, two hundred sixty-four million, four hundred thirty-one thousand, six hundred ninety-one".