256225391 has 2 divisors, whose sum is σ = 256225392. Its totient is φ = 256225390.

The previous prime is 256225381. The next prime is 256225427. The reversal of 256225391 is 193522652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256225391 - 2⁶ = 256225327 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256225301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128112695 + 128112696.

It is an arithmetic number, because the mean of its divisors is an integer number (128112696).

Almost surely, 2^256225391 is an apocalyptic number.

256225391 is a deficient number, since it is larger than the sum of its proper divisors (1).

256225391 is an equidigital number, since it uses as much as digits as its factorization.

256225391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32400, while the sum is 35.

The square root of 256225391 is about 16007.0419191055. The cubic root of 256225391 is about 635.1467129537.

It can be divided in two parts, 25622 and 5391, that added together give a palindrome (31013).

The spelling of 256225391 in words is "two hundred fifty-six million, two hundred twenty-five thousand, three hundred ninety-one".