663381 has 6 divisors (see below), whose sum is σ = 958230. Its totient is φ = 442248.

The previous prime is 663371. The next prime is 663407. The reversal of 663381 is 183366.

It can be written as a sum of positive squares in only one way, i.e., 378225 + 285156 = 615^2 + 534^2 .

It is not a de Polignac number, because 663381 - 2⁵ = 663349 is a prime.

It is a super-2 number, since 2×663381² = 880148702322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36846 + ... + 36863.

It is an arithmetic number, because the mean of its divisors is an integer number (159705).

2⁶⁶³³⁸¹ is an apocalyptic number.

It is an amenable number.

663381 is a deficient number, since it is larger than the sum of its proper divisors (294849).

663381 is a wasteful number, since it uses less digits than its factorization.

663381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73715 (or 73712 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 663381 is about 814.4820440010. The cubic root of 663381 is about 87.2142953445.

The spelling of 663381 in words is "six hundred sixty-three thousand, three hundred eighty-one".