657989 has 4 divisors (see below), whose sum is σ = 692640. Its totient is φ = 623340.

The previous prime is 657983. The next prime is 658001. The reversal of 657989 is 989756.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 657989 - 2⁴ = 657973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (657983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17297 + ... + 17334.

It is an arithmetic number, because the mean of its divisors is an integer number (173160).

2⁶⁵⁷⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

657989 is a deficient number, since it is larger than the sum of its proper divisors (34651).

657989 is a wasteful number, since it uses less digits than its factorization.

657989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34650.

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

The square root of 657989 is about 811.1652112856. The cubic root of 657989 is about 86.9773579163.

The spelling of 657989 in words is "six hundred fifty-seven thousand, nine hundred eighty-nine".