663657 has 4 divisors (see below), whose sum is σ = 884880. Its totient is φ = 442436.

The previous prime is 663653. The next prime is 663659. The reversal of 663657 is 756366.

663657 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

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 663657 - 2² = 663653 is a prime.

It is a super-2 number, since 2×663657² = 880881227298, which contains 22 as substring.

It is a D-number.

663657 is strictly pandigital in base 7.

663657 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (663653) 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, 110607 + ... + 110612.

It is an arithmetic number, because the mean of its divisors is an integer number (221220).

2⁶⁶³⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

663657 is a deficient number, since it is larger than the sum of its proper divisors (221223).

663657 is a wasteful number, since it uses less digits than its factorization.

663657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221222.

The product of its digits is 22680, while the sum is 33.

The square root of 663657 is about 814.6514592143. The cubic root of 663657 is about 87.2263888514.

The spelling of 663657 in words is "six hundred sixty-three thousand, six hundred fifty-seven".