1272505691 has 2 divisors, whose sum is σ = 1272505692. Its totient is φ = 1272505690.

The previous prime is 1272505669. The next prime is 1272505733. The reversal of 1272505691 is 1965052721.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1272505691 - 2¹⁸ = 1272243547 is a prime.

It is not a weakly prime, because it can be changed into another prime (1272505621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 636252845 + 636252846.

It is an arithmetic number, because the mean of its divisors is an integer number (636252846).

Almost surely, 2^1272505691 is an apocalyptic number.

1272505691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1272505691 is an equidigital number, since it uses as much as digits as its factorization.

1272505691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 1272505691 is about 35672.1977315668. The cubic root of 1272505691 is about 1083.6438679217.

The spelling of 1272505691 in words is "one billion, two hundred seventy-two million, five hundred five thousand, six hundred ninety-one".