664685280 has 576 divisors, whose sum is σ = 2807820288. Its totient is φ = 139898880.

The previous prime is 664685267. The next prime is 664685293. The reversal of 664685280 is 82586466.

664685280 is a `hidden beast` number, since 6 + 64 + 68 + 528 + 0 = 666.

664685280 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (664685267) and next prime (664685293).

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 polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10896450 + ... + 10896510.

It is an arithmetic number, because the mean of its divisors is an integer number (4874688).

Almost surely, 2^664685280 is an apocalyptic number.

664685280 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 664685280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1403910144).

664685280 is an abundant number, since it is smaller than the sum of its proper divisors (2143135008).

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

664685280 is a wasteful number, since it uses less digits than its factorization.

664685280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 45.

The square root of 664685280 is about 25781.4910352369. The cubic root of 664685280 is about 872.7141555794.

The spelling of 664685280 in words is "six hundred sixty-four million, six hundred eighty-five thousand, two hundred eighty".