663649920 has 288 divisors, whose sum is σ = 2390738220. Its totient is φ = 169623552.

The previous prime is 663649901. The next prime is 663649957. The reversal of 663649920 is 29946366.

663649920 is a `hidden beast` number, since 6 + 636 + 4 + 9 + 9 + 2 + 0 = 666.

663649920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 330076224 + 333573696 = 18168^2 + 18264^2 .

It is a tau number, because it is divible by the number of its divisors (288).

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4844092 + ... + 4844228.

Almost surely, 2^663649920 is an apocalyptic number.

663649920 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 663649920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1195369110).

663649920 is an abundant number, since it is smaller than the sum of its proper divisors (1727088300).

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

663649920 is a wasteful number, since it uses less digits than its factorization.

663649920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 45.

The square root of 663649920 is about 25761.4036884639. The cubic root of 663649920 is about 872.2607866854.

The spelling of 663649920 in words is "six hundred sixty-three million, six hundred forty-nine thousand, nine hundred twenty".