657998 has 12 divisors (see below), whose sum is σ = 1085280. Its totient is φ = 298980.

The previous prime is 657983. The next prime is 658001. The reversal of 657998 is 899756.

It is a super-2 number, since 2×657998² = 865922736008, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 657998.

It is an unprimeable number.

657998 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1118 + ... + 1601.

It is an arithmetic number, because the mean of its divisors is an integer number (90440).

2⁶⁵⁷⁹⁹⁸ is an apocalyptic number.

657998 is a deficient number, since it is larger than the sum of its proper divisors (427282).

657998 is a wasteful number, since it uses less digits than its factorization.

657998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2743 (or 2732 counting only the distinct ones).

The product of its digits is 136080, while the sum is 44.

The square root of 657998 is about 811.1707588418. The cubic root of 657998 is about 86.9777544745.

The spelling of 657998 in words is "six hundred fifty-seven thousand, nine hundred ninety-eight".