663865440 has 384 divisors, whose sum is σ = 2519838720. Its totient is φ = 143769600.

The previous prime is 663865429. The next prime is 663865441. The reversal of 663865440 is 44568366.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 663865392 and 663865401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663865441) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8403321 + ... + 8403399.

It is an arithmetic number, because the mean of its divisors is an integer number (6562080).

Almost surely, 2^663865440 is an apocalyptic number.

663865440 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 663865440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1259919360).

663865440 is an abundant number, since it is smaller than the sum of its proper divisors (1855973280).

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

663865440 is a wasteful number, since it uses less digits than its factorization.

663865440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 198 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 42.

The square root of 663865440 is about 25765.5863507897. The cubic root of 663865440 is about 872.3551985597.

The spelling of 663865440 in words is "six hundred sixty-three million, eight hundred sixty-five thousand, four hundred forty".