256655625161 has 4 divisors (see below), whose sum is σ = 276398365572. Its totient is φ = 236912884752.

The previous prime is 256655625151. The next prime is 256655625173. The reversal of 256655625161 is 161526556652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24635185936 + 232020439225 = 156956^2 + 481685^2 .

It is a cyclic number.

It is not a de Polignac number, because 256655625161 - 2⁶ = 256655625097 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 (256655625151) 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, 9871370186 + ... + 9871370211.

It is an arithmetic number, because the mean of its divisors is an integer number (69099591393).

Almost surely, 2^256655625161 is an apocalyptic number.

It is an amenable number.

256655625161 is a deficient number, since it is larger than the sum of its proper divisors (19742740411).

256655625161 is a wasteful number, since it uses less digits than its factorization.

256655625161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19742740410.

The product of its digits is 3240000, while the sum is 50.

The spelling of 256655625161 in words is "two hundred fifty-six billion, six hundred fifty-five million, six hundred twenty-five thousand, one hundred sixty-one".