1256645651 has 2 divisors, whose sum is σ = 1256645652. Its totient is φ = 1256645650.

The previous prime is 1256645639. The next prime is 1256645659. The reversal of 1256645651 is 1565466521.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1256645651 - 2¹⁴ = 1256629267 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1256645599 and 1256645608.

It is not a weakly prime, because it can be changed into another prime (1256645659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628322825 + 628322826.

It is an arithmetic number, because the mean of its divisors is an integer number (628322826).

Almost surely, 2^1256645651 is an apocalyptic number.

1256645651 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256645651 is an equidigital number, since it uses as much as digits as its factorization.

1256645651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216000, while the sum is 41.

The square root of 1256645651 is about 35449.1981714679. The cubic root of 1256645651 is about 1079.1229880054.

The spelling of 1256645651 in words is "one billion, two hundred fifty-six million, six hundred forty-five thousand, six hundred fifty-one".