256943551 has 4 divisors (see below), whose sum is σ = 257065704. Its totient is φ = 256821400.

The previous prime is 256943527. The next prime is 256943569. The reversal of 256943551 is 155349652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256943551 - 2⁹ = 256943039 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 (256943521) 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 3 ways as a sum of consecutive naturals, for example, 57865 + ... + 62146.

It is an arithmetic number, because the mean of its divisors is an integer number (64266426).

Almost surely, 2^256943551 is an apocalyptic number.

256943551 is a deficient number, since it is larger than the sum of its proper divisors (122153).

256943551 is a wasteful number, since it uses less digits than its factorization.

256943551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122152.

The product of its digits is 162000, while the sum is 40.

The square root of 256943551 is about 16029.4588492563. The cubic root of 256943551 is about 635.7395652905.

The spelling of 256943551 in words is "two hundred fifty-six million, nine hundred forty-three thousand, five hundred fifty-one".