657163681 has 4 divisors (see below), whose sum is σ = 657300292. Its totient is φ = 657027072.

The previous prime is 657163673. The next prime is 657163691. The reversal of 657163681 is 186361756.

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 466171281 + 190992400 = 21591^2 + 13820^2 .

It is a cyclic number.

It is not a de Polignac number, because 657163681 - 2³ = 657163673 is a prime.

It is a super-2 number, since 2×657163681² = 863728207250939522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (657163691) 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, 60816 + ... + 70801.

It is an arithmetic number, because the mean of its divisors is an integer number (164325073).

Almost surely, 2^657163681 is an apocalyptic number.

It is an amenable number.

657163681 is a deficient number, since it is larger than the sum of its proper divisors (136611).

657163681 is a wasteful number, since it uses less digits than its factorization.

657163681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136610.

The product of its digits is 181440, while the sum is 43.

The square root of 657163681 is about 25635.2039391147. The cubic root of 657163681 is about 869.4097731827.

The spelling of 657163681 in words is "six hundred fifty-seven million, one hundred sixty-three thousand, six hundred eighty-one".