669616128 has 144 divisors (see below), whose sum is σ = 2048695740. Its totient is φ = 209977344.

The previous prime is 669616127. The next prime is 669616139. The reversal of 669616128 is 821616966.

669616128 is a `hidden beast` number, since 6 + 6 + 9 + 616 + 1 + 28 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 656999424 + 12616704 = 25632^2 + 3552^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (669616127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 312276 + ... + 314412.

Almost surely, 2^669616128 is an apocalyptic number.

669616128 is a gapful number since it is divisible by the number (68) 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 669616128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1024347870).

669616128 is an abundant number, since it is smaller than the sum of its proper divisors (1379079612).

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

669616128 is a wasteful number, since it uses less digits than its factorization.

669616128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2182 (or 2159 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The square root of 669616128 is about 25876.9420140789. The cubic root of 669616128 is about 874.8668654040.

The spelling of 669616128 in words is "six hundred sixty-nine million, six hundred sixteen thousand, one hundred twenty-eight".