664689672 has 96 divisors (see below), whose sum is σ = 1879394400. Its totient is φ = 217667520.

The previous prime is 664689661. The next prime is 664689689. The reversal of 664689672 is 276986466.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 803323 + ... + 804149.

It is an arithmetic number, because the mean of its divisors is an integer number (19577025).

Almost surely, 2^664689672 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664689672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (939697200).

664689672 is an abundant number, since it is smaller than the sum of its proper divisors (1214704728).

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

664689672 is a wasteful number, since it uses less digits than its factorization.

664689672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 964 (or 893 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 54.

The square root of 664689672 is about 25781.5762124817. The cubic root of 664689672 is about 872.7160777683.

The spelling of 664689672 in words is "six hundred sixty-four million, six hundred eighty-nine thousand, six hundred seventy-two".