663881 has 2 divisors, whose sum is σ = 663882. Its totient is φ = 663880.

The previous prime is 663869. The next prime is 663893. The reversal of 663881 is 188366.

It is a balanced prime because it is at equal distance from previous prime (663869) and next prime (663893).

It can be written as a sum of positive squares in only one way, i.e., 547600 + 116281 = 740^2 + 341^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-663881 is a prime.

It is a super-2 number, since 2×663881² = 881475964322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (663821) 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 as a sum of consecutive naturals, namely, 331940 + 331941.

It is an arithmetic number, because the mean of its divisors is an integer number (331941).

2⁶⁶³⁸⁸¹ is an apocalyptic number.

It is an amenable number.

663881 is a deficient number, since it is larger than the sum of its proper divisors (1).

663881 is an equidigital number, since it uses as much as digits as its factorization.

663881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 663881 is about 814.7889297235. The cubic root of 663881 is about 87.2362014068.

The spelling of 663881 in words is "six hundred sixty-three thousand, eight hundred eighty-one".