256221019 has 2 divisors, whose sum is σ = 256221020. Its totient is φ = 256221018.

The previous prime is 256220999. The next prime is 256221067. The reversal of 256221019 is 910122652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256221019 - 2⁷ = 256220891 is a prime.

It is a super-2 number, since 2×256221019² = 131298421154796722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256221079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128110509 + 128110510.

It is an arithmetic number, because the mean of its divisors is an integer number (128110510).

Almost surely, 2^256221019 is an apocalyptic number.

256221019 is a deficient number, since it is larger than the sum of its proper divisors (1).

256221019 is an equidigital number, since it uses as much as digits as its factorization.

256221019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 256221019 is about 16006.9053536279. The cubic root of 256221019 is about 635.1431004088.

The spelling of 256221019 in words is "two hundred fifty-six million, two hundred twenty-one thousand, nineteen".