657398261601 has 15 divisors (see below), whose sum is σ = 982050279331. Its totient is φ = 438260642928.

The previous prime is 657398261593. The next prime is 657398261659. The reversal of 657398261601 is 106162893756.

The square root of 657398261601 is 810801.

It is a perfect power (a square), and thus also a powerful number.

657398261601 is a `hidden beast` number, since 6 + 5 + 7 + 3 + 9 + 8 + 26 + 1 + 601 = 666.

It can be written as a sum of positive squares in only one way, i.e., 397909901601 + 259488360000 = 630801^2 + 509400^2 .

It is not a de Polignac number, because 657398261601 - 2³ = 657398261593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (657398261701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 7252165 + ... + 7342253.

Almost surely, 2^657398261601 is an apocalyptic number.

657398261601 is the 810801-st square number.

657398261601 is the 405401-st centered octagonal number.

It is an amenable number.

657398261601 is a deficient number, since it is larger than the sum of its proper divisors (324652017730).

657398261601 is an frugal number, since it uses more digits than its factorization.

657398261601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180190 (or 90092 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 54.

The spelling of 657398261601 in words is "six hundred fifty-seven billion, three hundred ninety-eight million, two hundred sixty-one thousand, six hundred one".