656098721281 has 4 divisors (see below), whose sum is σ = 656648679492. Its totient is φ = 655548763072.

The previous prime is 656098721269. The next prime is 656098721347. The reversal of 656098721281 is 182127890656.

It is a happy number.

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 479937200625 + 176161520656 = 692775^2 + 419716^2 .

It is a cyclic number.

It is not a de Polignac number, because 656098721281 - 2¹⁹ = 656098196993 is a prime.

It is a super-2 number, since 2×656098721281² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656098721261) 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, 274977316 + ... + 274979701.

It is an arithmetic number, because the mean of its divisors is an integer number (164162169873).

Almost surely, 2^656098721281 is an apocalyptic number.

It is an amenable number.

656098721281 is a deficient number, since it is larger than the sum of its proper divisors (549958211).

656098721281 is a wasteful number, since it uses less digits than its factorization.

656098721281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549958210.

The product of its (nonzero) digits is 2903040, while the sum is 55.

The spelling of 656098721281 in words is "six hundred fifty-six billion, ninety-eight million, seven hundred twenty-one thousand, two hundred eighty-one".