256781539 has 16 divisors (see below), whose sum is σ = 302404608. Its totient is φ = 213478272.

The previous prime is 256781537. The next prime is 256781597. The reversal of 256781539 is 935187652.

It is not a de Polignac number, because 256781539 - 2¹ = 256781537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256781533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33724 + ... + 40630.

It is an arithmetic number, because the mean of its divisors is an integer number (18900288).

Almost surely, 2^256781539 is an apocalyptic number.

256781539 is a deficient number, since it is larger than the sum of its proper divisors (45623069).

256781539 is a wasteful number, since it uses less digits than its factorization.

256781539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7074.

The product of its digits is 453600, while the sum is 46.

The square root of 256781539 is about 16024.4044819145. The cubic root of 256781539 is about 635.6059184337.

The spelling of 256781539 in words is "two hundred fifty-six million, seven hundred eighty-one thousand, five hundred thirty-nine".