256121297 has 4 divisors (see below), whose sum is σ = 256244736. Its totient is φ = 255997860.

The previous prime is 256121293. The next prime is 256121309. The reversal of 256121297 is 792121652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 256121297 - 2² = 256121293 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256121291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58553 + ... + 62774.

It is an arithmetic number, because the mean of its divisors is an integer number (64061184).

Almost surely, 2^256121297 is an apocalyptic number.

It is an amenable number.

256121297 is a deficient number, since it is larger than the sum of its proper divisors (123439).

256121297 is a wasteful number, since it uses less digits than its factorization.

256121297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123438.

The product of its digits is 15120, while the sum is 35.

The square root of 256121297 is about 16003.7900823524. The cubic root of 256121297 is about 635.0606898408.

The spelling of 256121297 in words is "two hundred fifty-six million, one hundred twenty-one thousand, two hundred ninety-seven".