656723161 has 4 divisors (see below), whose sum is σ = 656777524. Its totient is φ = 656668800.

The previous prime is 656723149. The next prime is 656723203. The reversal of 656723161 is 161327656.

656723161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

656723161 is a nontrivial binomial coefficient, being equal to C(36242, 2).

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 79762761 + 576960400 = 8931^2 + 24020^2 .

It is a 3-Lehmer number, since φ(656723161) divides (656723161-1)³.

It is a cyclic number.

It is not a de Polignac number, because 656723161 - 2¹¹ = 656721113 is a prime.

It is a deceptive number, since it divides R_656723160.

It is a self number, because there is not a number n which added to its sum of digits gives 656723161.

It is not an unprimeable number, because it can be changed into a prime (656723861) 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, 1 + ... + 36241.

It is an arithmetic number, because the mean of its divisors is an integer number (164194381).

It is a Poulet number, since it divides 2^656723160-1.

Almost surely, 2^656723161 is an apocalyptic number.

656723161 is the 36241-st triangular number and also the 18121-st hexagonal number.

656723161 is the 12081-st centered nonagonal number.

It is an amenable number.

656723161 is a deficient number, since it is larger than the sum of its proper divisors (54363).

656723161 is a wasteful number, since it uses less digits than its factorization.

656723161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54362.

The product of its digits is 45360, while the sum is 37.

The square root of 656723161 is about 25626.6104079334. The cubic root of 656723161 is about 869.2154644110.

The spelling of 656723161 in words is "six hundred fifty-six million, seven hundred twenty-three thousand, one hundred sixty-one".