256143861 has 6 divisors (see below), whose sum is σ = 369985590. Its totient is φ = 170762568.

The previous prime is 256143857. The next prime is 256143961. The reversal of 256143861 is 168341652.

It is a happy number.

256143861 is a `hidden beast` number, since 2 + 5 + 614 + 38 + 6 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 255680100 + 463761 = 15990^2 + 681^2 .

It is not a de Polignac number, because 256143861 - 2² = 256143857 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256143841) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14230206 + ... + 14230223.

It is an arithmetic number, because the mean of its divisors is an integer number (61664265).

Almost surely, 2^256143861 is an apocalyptic number.

It is an amenable number.

256143861 is a deficient number, since it is larger than the sum of its proper divisors (113841729).

256143861 is a wasteful number, since it uses less digits than its factorization.

256143861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28460435 (or 28460432 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 256143861 is about 16004.4950248360. The cubic root of 256143861 is about 635.0793386722.

The spelling of 256143861 in words is "two hundred fifty-six million, one hundred forty-three thousand, eight hundred sixty-one".