664289280 has 360 divisors, whose sum is σ = 2484262872. Its totient is φ = 163577856.

The previous prime is 664289237. The next prime is 664289281. The reversal of 664289280 is 82982466.

664289280 is a `hidden beast` number, since 66 + 428 + 92 + 80 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 201867264 + 462422016 = 14208^2 + 21504^2 .

It is a tau number, because it is divible by the number of its divisors (360).

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

It is not an unprimeable number, because it can be changed into a prime (664289281) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12533734 + ... + 12533786.

Almost surely, 2^664289280 is an apocalyptic number.

664289280 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 664289280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1242131436).

664289280 is an abundant number, since it is smaller than the sum of its proper divisors (1819973592).

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

664289280 is a wasteful number, since it uses less digits than its factorization.

664289280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The square root of 664289280 is about 25773.8099628285. The cubic root of 664289280 is about 872.5408086484.

The spelling of 664289280 in words is "six hundred sixty-four million, two hundred eighty-nine thousand, two hundred eighty".