656479981 has 2 divisors, whose sum is σ = 656479982. Its totient is φ = 656479980.

The previous prime is 656479969. The next prime is 656480081. The reversal of 656479981 is 189974656.

656479981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 551827081 + 104652900 = 23491^2 + 10230^2 .

It is a cyclic number.

It is not a de Polignac number, because 656479981 - 2⁵ = 656479949 is a prime.

It is a super-2 number, since 2×656479981² = 861931930907520722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656479381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328239990 + 328239991.

It is an arithmetic number, because the mean of its divisors is an integer number (328239991).

Almost surely, 2^656479981 is an apocalyptic number.

It is an amenable number.

656479981 is a deficient number, since it is larger than the sum of its proper divisors (1).

656479981 is an equidigital number, since it uses as much as digits as its factorization.

656479981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3265920, while the sum is 55.

The square root of 656479981 is about 25621.8652911922. The cubic root of 656479981 is about 869.1081630270.

The spelling of 656479981 in words is "six hundred fifty-six million, four hundred seventy-nine thousand, nine hundred eighty-one".