256653409 has 2 divisors, whose sum is σ = 256653410. Its totient is φ = 256653408.

The previous prime is 256653407. The next prime is 256653431. The reversal of 256653409 is 904356652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 229613409 + 27040000 = 15153^2 + 5200^2 .

It is a cyclic number.

It is not a de Polignac number, because 256653409 - 2¹ = 256653407 is a prime.

Together with 256653407, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (256653407) 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, 128326704 + 128326705.

It is an arithmetic number, because the mean of its divisors is an integer number (128326705).

Almost surely, 2^256653409 is an apocalyptic number.

It is an amenable number.

256653409 is a deficient number, since it is larger than the sum of its proper divisors (1).

256653409 is an equidigital number, since it uses as much as digits as its factorization.

256653409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 194400, while the sum is 40.

The square root of 256653409 is about 16020.4060185752. The cubic root of 256653409 is about 635.5001816841.

The spelling of 256653409 in words is "two hundred fifty-six million, six hundred fifty-three thousand, four hundred nine".