663887681 has 8 divisors (see below), whose sum is σ = 668428800. Its totient is φ = 659359008.

The previous prime is 663887669. The next prime is 663887729. The reversal of 663887681 is 186788366.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 663887681 - 2¹⁴ = 663871297 is a prime.

It is a super-2 number, since 2×663887681² = 881493705967115522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (663880681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 120080 + ... + 125486.

It is an arithmetic number, because the mean of its divisors is an integer number (83553600).

Almost surely, 2^663887681 is an apocalyptic number.

It is an amenable number.

663887681 is a deficient number, since it is larger than the sum of its proper divisors (4541119).

663887681 is a wasteful number, since it uses less digits than its factorization.

663887681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6223.

The product of its digits is 2322432, while the sum is 53.

The square root of 663887681 is about 25766.0179500054. The cubic root of 663887681 is about 872.3649404111.

The spelling of 663887681 in words is "six hundred sixty-three million, eight hundred eighty-seven thousand, six hundred eighty-one".