664889760 has 144 divisors (see below), whose sum is σ = 2296685664. Its totient is φ = 175136256.

The previous prime is 664889749. The next prime is 664889783. The reversal of 664889760 is 67988466.

It is a tau number, because it is divible by the number of its divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 664889697 and 664889706.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 116739 + ... + 122301.

It is an arithmetic number, because the mean of its divisors is an integer number (15949206).

Almost surely, 2^664889760 is an apocalyptic number.

664889760 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 664889760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1148342832).

664889760 is an abundant number, since it is smaller than the sum of its proper divisors (1631795904).

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

664889760 is a wasteful number, since it uses less digits than its factorization.

664889760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5667 (or 5656 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The square root of 664889760 is about 25785.4563659440. The cubic root of 664889760 is about 872.8036386774.

The spelling of 664889760 in words is "six hundred sixty-four million, eight hundred eighty-nine thousand, seven hundred sixty".