663981903 has 36 divisors (see below), whose sum is σ = 1099668960. Its totient is φ = 384553728.

The previous prime is 663981887. The next prime is 663981911. The reversal of 663981903 is 309189366.

663981903 is a `hidden beast` number, since 6 + 639 + 8 + 1 + 9 + 0 + 3 = 666.

It is not a de Polignac number, because 663981903 - 2⁴ = 663981887 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663981943) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 13018 + ... + 38696.

It is an arithmetic number, because the mean of its divisors is an integer number (30546360).

Almost surely, 2^663981903 is an apocalyptic number.

663981903 is a deficient number, since it is larger than the sum of its proper divisors (435687057).

663981903 is a wasteful number, since it uses less digits than its factorization.

663981903 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25728 (or 25712 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The square root of 663981903 is about 25767.8463011560. The cubic root of 663981903 is about 872.4062084767.

The spelling of 663981903 in words is "six hundred sixty-three million, nine hundred eighty-one thousand, nine hundred three".