655978 has 8 divisors (see below), whose sum is σ = 997668. Its totient is φ = 323424.

The previous prime is 655961. The next prime is 655987. The reversal of 655978 is 879556.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 558009 + 97969 = 747^2 + 313^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 655978.

It is an unprimeable number.

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, 2101 + ... + 2392.

2⁶⁵⁵⁹⁷⁸ is an apocalyptic number.

655978 is a deficient number, since it is larger than the sum of its proper divisors (341690).

655978 is a wasteful number, since it uses less digits than its factorization.

655978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4568.

The product of its digits is 75600, while the sum is 40.

The square root of 655978 is about 809.9246878568. The cubic root of 655978 is about 86.8886583774. Note that the first 3 decimals are identical.

The spelling of 655978 in words is "six hundred fifty-five thousand, nine hundred seventy-eight".