669921876 has 72 divisors (see below), whose sum is σ = 1848752360. Its totient is φ = 203295744.

The previous prime is 669921871. The next prime is 669921881. The reversal of 669921876 is 678129966.

It is a Cunningham number, because it is equal to 875³+1.

It is an interprime number because it is at equal distance from previous prime (669921871) and next prime (669921881).

It can be written as a sum of positive squares in 4 ways, for example, as 215208900 + 454712976 = 14670^2 + 21324^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669921871) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24360 + ... + 43968.

Almost surely, 2^669921876 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 669921876, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (924376180).

669921876 is an abundant number, since it is smaller than the sum of its proper divisors (1178830484).

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

669921876 is a wasteful number, since it uses less digits than its factorization.

669921876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19705 (or 19700 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The square root of 669921876 is about 25882.8490703786. The cubic root of 669921876 is about 875.0000004354. Note that the first 6 decimals are identical.

The spelling of 669921876 in words is "six hundred sixty-nine million, nine hundred twenty-one thousand, eight hundred seventy-six".