256005761 has 4 divisors (see below), whose sum is σ = 279279024. Its totient is φ = 232732500.

The previous prime is 256005749. The next prime is 256005767. The reversal of 256005761 is 167500652.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 256005761 - 2⁶ = 256005697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256005767) 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, 11636615 + ... + 11636636.

It is an arithmetic number, because the mean of its divisors is an integer number (69819756).

Almost surely, 2^256005761 is an apocalyptic number.

It is an amenable number.

256005761 is a deficient number, since it is larger than the sum of its proper divisors (23273263).

256005761 is a wasteful number, since it uses less digits than its factorization.

256005761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23273262.

The product of its (nonzero) digits is 12600, while the sum is 32.

The square root of 256005761 is about 16000.1800302372. The cubic root of 256005761 is about 634.9651837815.

The spelling of 256005761 in words is "two hundred fifty-six million, five thousand, seven hundred sixty-one".