663891020 has 24 divisors (see below), whose sum is σ = 1501415664. Its totient is φ = 245128896.

The previous prime is 663891017. The next prime is 663891029. The reversal of 663891020 is 20198366.

It is not an unprimeable number, because it can be changed into a prime (663891029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1276454 + ... + 1276973.

It is an arithmetic number, because the mean of its divisors is an integer number (62558986).

Almost surely, 2^663891020 is an apocalyptic number.

It is an amenable number.

663891020 is an abundant number, since it is smaller than the sum of its proper divisors (837524644).

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

663891020 is a wasteful number, since it uses less digits than its factorization.

663891020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2553449 (or 2553447 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 663891020 is about 25766.0827445695. The cubic root of 663891020 is about 872.3664029183.

The spelling of 663891020 in words is "six hundred sixty-three million, eight hundred ninety-one thousand, twenty".