1256813 has 2 divisors, whose sum is σ = 1256814. Its totient is φ = 1256812.

The previous prime is 1256809. The next prime is 1256819. The reversal of 1256813 is 3186521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1249924 + 6889 = 1118^2 + 83^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256813 - 2² = 1256809 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1256819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628406 + 628407.

It is an arithmetic number, because the mean of its divisors is an integer number (628407).

2^1256813 is an apocalyptic number.

It is an amenable number.

1256813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256813 is an equidigital number, since it uses as much as digits as its factorization.

1256813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 26.

The square root of 1256813 is about 1121.0767145918. The cubic root of 1256813 is about 107.9170888578.

The spelling of 1256813 in words is "one million, two hundred fifty-six thousand, eight hundred thirteen".