663881864 has 24 divisors (see below), whose sum is σ = 1286242830. Its totient is φ = 321229440.

The previous prime is 663881863. The next prime is 663881873. The reversal of 663881864 is 468188366.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 406022500 + 257859364 = 20150^2 + 16058^2 .

It is a super-2 number, since 2×663881864² = 881478258696228992, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (663881863) 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, 35489 + ... + 50864.

Almost surely, 2^663881864 is an apocalyptic number.

It is an amenable number.

663881864 is a deficient number, since it is larger than the sum of its proper divisors (622360966).

663881864 is a wasteful number, since it uses less digits than its factorization.

663881864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86421 (or 86386 counting only the distinct ones).

The product of its digits is 1327104, while the sum is 50.

The square root of 663881864 is about 25765.9050685203. The cubic root of 663881864 is about 872.3623925094.

The spelling of 663881864 in words is "six hundred sixty-three million, eight hundred eighty-one thousand, eight hundred sixty-four".