655998 has 16 divisors (see below), whose sum is σ = 1499520. Its totient is φ = 187416.

The previous prime is 655987. The next prime is 656023. The reversal of 655998 is 899556.

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 15619 = 655998 / (6 + 5 + 5 + 9 + 9 + 8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7768 + ... + 7851.

It is an arithmetic number, because the mean of its divisors is an integer number (93720).

2⁶⁵⁵⁹⁹⁸ is an apocalyptic number.

655998 is an abundant number, since it is smaller than the sum of its proper divisors (843522).

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

655998 is a wasteful number, since it uses less digits than its factorization.

655998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15631.

The product of its digits is 97200, while the sum is 42.

The square root of 655998 is about 809.9370345897. The cubic root of 655998 is about 86.8895414128.

It can be divided in two parts, 655 and 998, that added together give a triangular number (1653 = T₅₇).

The spelling of 655998 in words is "six hundred fifty-five thousand, nine hundred ninety-eight".