664087680 has 128 divisors (see below), whose sum is σ = 2352038400. Its totient is φ = 177085440.

The previous prime is 664087649. The next prime is 664087681. The reversal of 664087680 is 86780466.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

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 (664087681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1936 + ... + 36495.

It is an arithmetic number, because the mean of its divisors is an integer number (18375300).

Almost surely, 2^664087680 is an apocalyptic number.

664087680 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 664087680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1176019200).

664087680 is an abundant number, since it is smaller than the sum of its proper divisors (1687950720).

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

664087680 is a wasteful number, since it uses less digits than its factorization.

664087680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38459 (or 38441 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 664087680 is about 25769.8987192422. The cubic root of 664087680 is about 872.4525328375.

It can be divided in two parts, 66408 and 7680, that added together give a cube (74088 = 42³).

The spelling of 664087680 in words is "six hundred sixty-four million, eighty-seven thousand, six hundred eighty".