256123919 has 2 divisors, whose sum is σ = 256123920. Its totient is φ = 256123918.

The previous prime is 256123871. The next prime is 256123927. The reversal of 256123919 is 919321652.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256123919 is a prime.

It is a super-2 number, since 2×256123919² = 131198923767837122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256123979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128061959 + 128061960.

It is an arithmetic number, because the mean of its divisors is an integer number (128061960).

Almost surely, 2^256123919 is an apocalyptic number.

256123919 is a deficient number, since it is larger than the sum of its proper divisors (1).

256123919 is an equidigital number, since it uses as much as digits as its factorization.

256123919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29160, while the sum is 38.

The square root of 256123919 is about 16003.8720002379. The cubic root of 256123919 is about 635.0628569435.

The spelling of 256123919 in words is "two hundred fifty-six million, one hundred twenty-three thousand, nine hundred nineteen".