256005251 has 2 divisors, whose sum is σ = 256005252. Its totient is φ = 256005250.

The previous prime is 256005247. The next prime is 256005313. The reversal of 256005251 is 152500652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256005251 - 2² = 256005247 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256005251.

It is not a weakly prime, because it can be changed into another prime (256005241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128002625 + 128002626.

It is an arithmetic number, because the mean of its divisors is an integer number (128002626).

Almost surely, 2^256005251 is an apocalyptic number.

256005251 is a deficient number, since it is larger than the sum of its proper divisors (1).

256005251 is an equidigital number, since it uses as much as digits as its factorization.

256005251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3000, while the sum is 26.

The square root of 256005251 is about 16000.1640929085. The cubic root of 256005251 is about 634.9647621341.

The spelling of 256005251 in words is "two hundred fifty-six million, five thousand, two hundred fifty-one".