256556089 has 4 divisors (see below), whose sum is σ = 257202724. Its totient is φ = 255909456.

The previous prime is 256556063. The next prime is 256556101. The reversal of 256556089 is 980655652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 197880489 + 58675600 = 14067^2 + 7660^2 .

It is a cyclic number.

It is not a de Polignac number, because 256556089 - 2⁹ = 256555577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256556009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 322722 + ... + 323515.

It is an arithmetic number, because the mean of its divisors is an integer number (64300681).

Almost surely, 2^256556089 is an apocalyptic number.

It is an amenable number.

256556089 is a deficient number, since it is larger than the sum of its proper divisors (646635).

256556089 is an equidigital number, since it uses as much as digits as its factorization.

256556089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646634.

The product of its (nonzero) digits is 648000, while the sum is 46.

The square root of 256556089 is about 16017.3683543833. The cubic root of 256556089 is about 635.4198467598.

The spelling of 256556089 in words is "two hundred fifty-six million, five hundred fifty-six thousand, eighty-nine".