663891840 has 96 divisors (see below), whose sum is σ = 2292521400. Its totient is φ = 177036288.

The previous prime is 663891829. The next prime is 663891869. The reversal of 663891840 is 48198366.

663891840 is a `hidden beast` number, since 6 + 638 + 9 + 1 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 51870 + ... + 63389.

Almost surely, 2^663891840 is an apocalyptic number.

663891840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

663891840 is an abundant number, since it is smaller than the sum of its proper divisors (1628629560).

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

663891840 is a wasteful number, since it uses less digits than its factorization.

663891840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115284 (or 115269 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 663891840 is about 25766.0986569562. The cubic root of 663891840 is about 872.3667620838.

The spelling of 663891840 in words is "six hundred sixty-three million, eight hundred ninety-one thousand, eight hundred forty".