1256621 has 2 divisors, whose sum is σ = 1256622. Its totient is φ = 1256620.

The previous prime is 1256617. The next prime is 1256659. The reversal of 1256621 is 1266521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1240996 + 15625 = 1114^2 + 125^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256621 - 2² = 1256617 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1256611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628310 + 628311.

It is an arithmetic number, because the mean of its divisors is an integer number (628311).

2^1256621 is an apocalyptic number.

It is an amenable number.

1256621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256621 is an equidigital number, since it uses as much as digits as its factorization.

1256621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 23.

The square root of 1256621 is about 1120.9910793579. The cubic root of 1256621 is about 107.9115931751.

The spelling of 1256621 in words is "one million, two hundred fifty-six thousand, six hundred twenty-one".