256543551 has 16 divisors (see below), whose sum is σ = 414616320. Its totient is φ = 155480760.

The previous prime is 256543537. The next prime is 256543559. The reversal of 256543551 is 155345652.

256543551 is a `hidden beast` number, since 2 + 5 + 65 + 43 + 551 = 666.

It is not a de Polignac number, because 256543551 - 2⁶ = 256543487 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256543559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 431595 + ... + 432188.

It is an arithmetic number, because the mean of its divisors is an integer number (25913520).

Almost surely, 2^256543551 is an apocalyptic number.

256543551 is a deficient number, since it is larger than the sum of its proper divisors (158072769).

256543551 is a wasteful number, since it uses less digits than its factorization.

256543551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 863803 (or 863797 counting only the distinct ones).

The product of its digits is 90000, while the sum is 36.

The square root of 256543551 is about 16016.9769619613. The cubic root of 256543551 is about 635.4094955161.

The spelling of 256543551 in words is "two hundred fifty-six million, five hundred forty-three thousand, five hundred fifty-one".