669991608 has 256 divisors, whose sum is σ = 2217600000. Its totient is φ = 184757760.

The previous prime is 669991601. The next prime is 669991613. The reversal of 669991608 is 806199966.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669991601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3366693 + ... + 3366891.

It is an arithmetic number, because the mean of its divisors is an integer number (8662500).

Almost surely, 2^669991608 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 669991608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1108800000).

669991608 is an abundant number, since it is smaller than the sum of its proper divisors (1547608392).

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

669991608 is a wasteful number, since it uses less digits than its factorization.

669991608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 337 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 54.

The square root of 669991608 is about 25884.1961049595. The cubic root of 669991608 is about 875.0303588922.

The spelling of 669991608 in words is "six hundred sixty-nine million, nine hundred ninety-one thousand, six hundred eight".