657980 has 24 divisors (see below), whose sum is σ = 1397088. Its totient is φ = 260288.

The previous prime is 657973. The next prime is 657983. The reversal of 657980 is 89756.

It is a self number, because there is not a number n which added to its sum of digits gives 657980.

It is a congruent number.

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

657980 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 7 ways as a sum of consecutive naturals, for example, 3242 + ... + 3438.

It is an arithmetic number, because the mean of its divisors is an integer number (58212).

2⁶⁵⁷⁹⁸⁰ is an apocalyptic number.

It is an amenable number.

657980 is an abundant number, since it is smaller than the sum of its proper divisors (739108).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

657980 is a wasteful number, since it uses less digits than its factorization.

657980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 657980 is about 811.1596636914. The cubic root of 657980 is about 86.9769613546.

The spelling of 657980 in words is "six hundred fifty-seven thousand, nine hundred eighty".