1256132809 has 2 divisors, whose sum is σ = 1256132810. Its totient is φ = 1256132808.

The previous prime is 1256132791. The next prime is 1256132819. The reversal of 1256132809 is 9082316521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 791859600 + 464273209 = 28140^2 + 21547^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256132809 - 2⁵ = 1256132777 is a prime.

It is not a weakly prime, because it can be changed into another prime (1256132819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628066404 + 628066405.

It is an arithmetic number, because the mean of its divisors is an integer number (628066405).

Almost surely, 2^1256132809 is an apocalyptic number.

It is an amenable number.

1256132809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256132809 is an equidigital number, since it uses as much as digits as its factorization.

1256132809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 1256132809 is about 35441.9639551761. The cubic root of 1256132809 is about 1078.9761699287.

The spelling of 1256132809 in words is "one billion, two hundred fifty-six million, one hundred thirty-two thousand, eight hundred nine".