669651840 has 512 divisors, whose sum is σ = 2796595200. Its totient is φ = 149299200.

The previous prime is 669651803. The next prime is 669651841. The reversal of 669651840 is 48156966.

669651840 is a `hidden beast` number, since 6 + 6 + 96 + 518 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669651841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2470905 + ... + 2471175.

It is an arithmetic number, because the mean of its divisors is an integer number (5462100).

Almost surely, 2^669651840 is an apocalyptic number.

669651840 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 669651840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1398297600).

669651840 is an abundant number, since it is smaller than the sum of its proper divisors (2126943360).

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

669651840 is a wasteful number, since it uses less digits than its factorization.

669651840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323 (or 305 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 669651840 is about 25877.6320400457. The cubic root of 669651840 is about 874.8824179416.

The spelling of 669651840 in words is "six hundred sixty-nine million, six hundred fifty-one thousand, eight hundred forty".