1256513801 has 2 divisors, whose sum is σ = 1256513802. Its totient is φ = 1256513800.

The previous prime is 1256513777. The next prime is 1256513803. The reversal of 1256513801 is 1083156521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 796368400 + 460145401 = 28220^2 + 21451^2 .

It is an emirp because it is prime and its reverse (1083156521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1256513801 - 2³⁰ = 182771977 is a prime.

Together with 1256513803, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1256513803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628256900 + 628256901.

It is an arithmetic number, because the mean of its divisors is an integer number (628256901).

Almost surely, 2^1256513801 is an apocalyptic number.

It is an amenable number.

1256513801 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256513801 is an equidigital number, since it uses as much as digits as its factorization.

1256513801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 1256513801 is about 35447.3384191253. The cubic root of 1256513801 is about 1079.0852453735.

The spelling of 1256513801 in words is "one billion, two hundred fifty-six million, five hundred thirteen thousand, eight hundred one".