256345551 has 48 divisors (see below), whose sum is σ = 468619008. Its totient is φ = 131155200.

The previous prime is 256345519. The next prime is 256345553. The reversal of 256345551 is 155543652.

256345551 is a `hidden beast` number, since 2 + 5 + 63 + 45 + 551 = 666.

It is not a de Polignac number, because 256345551 - 2⁵ = 256345519 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256345553) 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 47 ways as a sum of consecutive naturals, for example, 43671 + ... + 49191.

It is an arithmetic number, because the mean of its divisors is an integer number (9762896).

Almost surely, 2^256345551 is an apocalyptic number.

256345551 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

256345551 is a deficient number, since it is larger than the sum of its proper divisors (212273457).

256345551 is a wasteful number, since it uses less digits than its factorization.

256345551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5612 (or 5609 counting only the distinct ones).

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

The square root of 256345551 is about 16010.7948272408. The cubic root of 256345551 is about 635.2459840181.

The spelling of 256345551 in words is "two hundred fifty-six million, three hundred forty-five thousand, five hundred fifty-one".