256897689 has 16 divisors (see below), whose sum is σ = 372993600. Its totient is φ = 156655296.

The previous prime is 256897679. The next prime is 256897709. The reversal of 256897689 is 986798652.

It is a happy number.

It is not a de Polignac number, because 256897689 - 2¹³ = 256889497 is a prime.

It is a super-2 number, since 2×256897689² = 131992845227081442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (256897639) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76054 + ... + 79359.

It is an arithmetic number, because the mean of its divisors is an integer number (23312100).

Almost surely, 2^256897689 is an apocalyptic number.

256897689 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

256897689 is a deficient number, since it is larger than the sum of its proper divisors (116095911).

256897689 is a wasteful number, since it uses less digits than its factorization.

256897689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155464.

The product of its digits is 13063680, while the sum is 60.

The square root of 256897689 is about 16028.0282318194. The cubic root of 256897689 is about 635.7017385347.

The spelling of 256897689 in words is "two hundred fifty-six million, eight hundred ninety-seven thousand, six hundred eighty-nine".