669721824 has 96 divisors (see below), whose sum is σ = 2020788000. Its totient is φ = 215534592.

The previous prime is 669721739. The next prime is 669721831. The reversal of 669721824 is 428127966.

It is a happy number.

669721824 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a self number, because there is not a number n which added to its sum of digits gives 669721824.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11692 + ... + 38420.

It is an arithmetic number, because the mean of its divisors is an integer number (21049875).

Almost surely, 2^669721824 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 669721824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1010394000).

669721824 is an abundant number, since it is smaller than the sum of its proper divisors (1351066176).

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

669721824 is a wasteful number, since it uses less digits than its factorization.

669721824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26777 (or 26763 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 669721824 is about 25878.9842149958. The cubic root of 669721824 is about 874.9128942950.

The spelling of 669721824 in words is "six hundred sixty-nine million, seven hundred twenty-one thousand, eight hundred twenty-four".