256165121 has 12 divisors (see below), whose sum is σ = 266620500. Its totient is φ = 246100320.

The previous prime is 256165111. The next prime is 256165127. The reversal of 256165121 is 121561652.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 142444225 + 113720896 = 11935^2 + 10664^2 .

It is not a de Polignac number, because 256165121 - 2⁶ = 256165057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256165127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 142295 + ... + 144083.

It is an arithmetic number, because the mean of its divisors is an integer number (22218375).

Almost surely, 2^256165121 is an apocalyptic number.

It is an amenable number.

256165121 is a deficient number, since it is larger than the sum of its proper divisors (10455379).

256165121 is a wasteful number, since it uses less digits than its factorization.

256165121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2000 (or 1969 counting only the distinct ones).

The product of its digits is 3600, while the sum is 29.

The square root of 256165121 is about 16005.1591994582. The cubic root of 256165121 is about 635.0969087636.

The spelling of 256165121 in words is "two hundred fifty-six million, one hundred sixty-five thousand, one hundred twenty-one".