256161005 has 16 divisors (see below), whose sum is σ = 321940224. Its totient is φ = 195296640.

The previous prime is 256160999. The next prime is 256161011. The reversal of 256161005 is 500161652.

It is an interprime number because it is at equal distance from previous prime (256160999) and next prime (256161011).

It is not a de Polignac number, because 256161005 - 2²⁶ = 189052141 is a prime.

It is a super-2 number, since 2×256161005² = 131236920965220050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28352 + ... + 36278.

It is an arithmetic number, because the mean of its divisors is an integer number (20121264).

Almost surely, 2^256161005 is an apocalyptic number.

It is an amenable number.

256161005 is a deficient number, since it is larger than the sum of its proper divisors (65779219).

256161005 is a wasteful number, since it uses less digits than its factorization.

256161005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8236.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 256161005 is about 16005.0306154034. The cubic root of 256161005 is about 635.0935072169.

The spelling of 256161005 in words is "two hundred fifty-six million, one hundred sixty-one thousand, five".