665929728 has 96 divisors (see below), whose sum is σ = 1972807200. Its totient is φ = 221958144.

The previous prime is 665929721. The next prime is 665929739. The reversal of 665929728 is 827929566.

It is a tau number, because it is divible by the number of its divisors (96).

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

It is not an unprimeable number, because it can be changed into a prime (665929721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49275 + ... + 61317.

It is an arithmetic number, because the mean of its divisors is an integer number (20550075).

Almost surely, 2^665929728 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 665929728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (986403600).

665929728 is an abundant number, since it is smaller than the sum of its proper divisors (1306877472).

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

665929728 is a wasteful number, since it uses less digits than its factorization.

665929728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12074 (or 12048 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 54.

The square root of 665929728 is about 25805.6142728671. The cubic root of 665929728 is about 873.2584584462.

The spelling of 665929728 in words is "six hundred sixty-five million, nine hundred twenty-nine thousand, seven hundred twenty-eight".