669390816 has 48 divisors (see below), whose sum is σ = 1764882000. Its totient is φ = 222148608.

The previous prime is 669390809. The next prime is 669390829. The reversal of 669390816 is 618093966.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6760 + ... + 37208.

It is an arithmetic number, because the mean of its divisors is an integer number (36768375).

Almost surely, 2^669390816 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 669390816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (882441000).

669390816 is an abundant number, since it is smaller than the sum of its proper divisors (1095491184).

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

669390816 is a wasteful number, since it uses less digits than its factorization.

669390816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30691 (or 30683 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 48.

The square root of 669390816 is about 25872.5881194750. The cubic root of 669390816 is about 874.7687295179.

The spelling of 669390816 in words is "six hundred sixty-nine million, three hundred ninety thousand, eight hundred sixteen".