669823440 has 320 divisors, whose sum is σ = 2527338240. Its totient is φ = 144506880.

The previous prime is 669823423. The next prime is 669823447. The reversal of 669823440 is 44328966.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 669823392 and 669823401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669823447) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 994944 + ... + 995616.

It is an arithmetic number, because the mean of its divisors is an integer number (7897932).

Almost surely, 2^669823440 is an apocalyptic number.

669823440 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 669823440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1263669120).

669823440 is an abundant number, since it is smaller than the sum of its proper divisors (1857514800).

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

669823440 is a wasteful number, since it uses less digits than its factorization.

669823440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742 (or 736 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The square root of 669823440 is about 25880.9474324260. The cubic root of 669823440 is about 874.9571418464.

The spelling of 669823440 in words is "six hundred sixty-nine million, eight hundred twenty-three thousand, four hundred forty".