256705749 has 6 divisors (see below), whose sum is σ = 370797206. Its totient is φ = 171137160.

The previous prime is 256705727. The next prime is 256705753. The reversal of 256705749 is 947507652.

256705749 is a `hidden beast` number, since 2 + 5 + 6 + 70 + 574 + 9 = 666.

256705749 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 165636900 + 91068849 = 12870^2 + 9543^2 .

It is not a de Polignac number, because 256705749 - 2⁵ = 256705717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256705759) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14261422 + ... + 14261439.

Almost surely, 2^256705749 is an apocalyptic number.

It is an amenable number.

256705749 is a deficient number, since it is larger than the sum of its proper divisors (114091457).

256705749 is a wasteful number, since it uses less digits than its factorization.

256705749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28522867 (or 28522864 counting only the distinct ones).

The product of its (nonzero) digits is 529200, while the sum is 45.

The square root of 256705749 is about 16022.0394769205. The cubic root of 256705749 is about 635.5433784851.

The spelling of 256705749 in words is "two hundred fifty-six million, seven hundred five thousand, seven hundred forty-nine".