663656 has 24 divisors (see below), whose sum is σ = 1448370. Its totient is φ = 284256.

The previous prime is 663653. The next prime is 663659. The reversal of 663656 is 656366.

It is an interprime number because it is at equal distance from previous prime (663653) and next prime (663659).

It can be written as a sum of positive squares in only one way, i.e., 592900 + 70756 = 770^2 + 266^2 .

It is not an unprimeable number, because it can be changed into a prime (663653) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 455 + ... + 1238.

2⁶⁶³⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

663656 is an abundant number, since it is smaller than the sum of its proper divisors (784714).

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

663656 is a wasteful number, since it uses less digits than its factorization.

663656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1713 (or 1702 counting only the distinct ones).

The product of its digits is 19440, while the sum is 32.

The square root of 663656 is about 814.6508454547. The cubic root of 663656 is about 87.2263450404.

The spelling of 663656 in words is "six hundred sixty-three thousand, six hundred fifty-six".