256783988 has 6 divisors (see below), whose sum is σ = 449371986. Its totient is φ = 128391992.

The previous prime is 256783987. The next prime is 256784023. The reversal of 256783988 is 889387652.

It can be written as a sum of positive squares in only one way, i.e., 236605924 + 20178064 = 15382^2 + 4492^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256783981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32097995 + ... + 32098002.

It is an arithmetic number, because the mean of its divisors is an integer number (74895331).

Almost surely, 2^256783988 is an apocalyptic number.

It is an amenable number.

256783988 is a deficient number, since it is larger than the sum of its proper divisors (192587998).

256783988 is a wasteful number, since it uses less digits than its factorization.

256783988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64196001 (or 64195999 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 56.

The square root of 256783988 is about 16024.4808964284. The cubic root of 256783988 is about 635.6079390799.

The spelling of 256783988 in words is "two hundred fifty-six million, seven hundred eighty-three thousand, nine hundred eighty-eight".