256217157 has 24 divisors (see below), whose sum is σ = 423660224. Its totient is φ = 146168064.

The previous prime is 256217131. The next prime is 256217161. The reversal of 256217157 is 751712652.

256217157 is a `hidden beast` number, since 25 + 621 + 7 + 1 + 5 + 7 = 666.

It is not a de Polignac number, because 256217157 - 2¹⁴ = 256200773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256217657) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39378 + ... + 45420.

Almost surely, 2^256217157 is an apocalyptic number.

It is an amenable number.

256217157 is a deficient number, since it is larger than the sum of its proper divisors (167443067).

256217157 is a wasteful number, since it uses less digits than its factorization.

256217157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6729 (or 6726 counting only the distinct ones).

The product of its digits is 29400, while the sum is 36.

The square root of 256217157 is about 16006.7847177377. The cubic root of 256217157 is about 635.1399092381.

The spelling of 256217157 in words is "two hundred fifty-six million, two hundred seventeen thousand, one hundred fifty-seven".