256220999 has 2 divisors, whose sum is σ = 256221000. Its totient is φ = 256220998.

The previous prime is 256220977. The next prime is 256221019. The reversal of 256220999 is 999022652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256220999 - 2⁸ = 256220743 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256220969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128110499 + 128110500.

It is an arithmetic number, because the mean of its divisors is an integer number (128110500).

Almost surely, 2^256220999 is an apocalyptic number.

256220999 is a deficient number, since it is larger than the sum of its proper divisors (1).

256220999 is an equidigital number, since it uses as much as digits as its factorization.

256220999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 174960, while the sum is 44.

The square root of 256220999 is about 16006.9047288975. The cubic root of 256220999 is about 635.1430838829.

The spelling of 256220999 in words is "two hundred fifty-six million, two hundred twenty thousand, nine hundred ninety-nine".