656444161 has 4 divisors (see below), whose sum is σ = 660625492. Its totient is φ = 652262832.

The previous prime is 656444123. The next prime is 656444227. The reversal of 656444161 is 161444656.

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 96648561 + 559795600 = 9831^2 + 23660^2 .

It is a cyclic number.

It is not a de Polignac number, because 656444161 - 2⁹ = 656443649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 656444161.

It is not an unprimeable number, because it can be changed into a prime (656444111) 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, 2090430 + ... + 2090743.

It is an arithmetic number, because the mean of its divisors is an integer number (165156373).

Almost surely, 2^656444161 is an apocalyptic number.

It is an amenable number.

656444161 is a deficient number, since it is larger than the sum of its proper divisors (4181331).

656444161 is a wasteful number, since it uses less digits than its factorization.

656444161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4181330.

The product of its digits is 69120, while the sum is 37.

The square root of 656444161 is about 25621.1662693172. The cubic root of 656444161 is about 869.0923554768.

The spelling of 656444161 in words is "six hundred fifty-six million, four hundred forty-four thousand, one hundred sixty-one".