663437640 has 128 divisors (see below), whose sum is σ = 2068934400. Its totient is φ = 169989120.

The previous prime is 663437609. The next prime is 663437681. The reversal of 663437640 is 46734366.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1081974 + ... + 1082586.

It is an arithmetic number, because the mean of its divisors is an integer number (16163550).

Almost surely, 2^663437640 is an apocalyptic number.

663437640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 663437640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1034467200).

663437640 is an abundant number, since it is smaller than the sum of its proper divisors (1405496760).

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

663437640 is a wasteful number, since it uses less digits than its factorization.

663437640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 967 (or 963 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 39.

The square root of 663437640 is about 25757.2832418328. The cubic root of 663437640 is about 872.1677741596.

The spelling of 663437640 in words is "six hundred sixty-three million, four hundred thirty-seven thousand, six hundred forty".