669965820 has 96 divisors (see below), whose sum is σ = 1910200320. Its totient is φ = 175418880.

The previous prime is 669965797. The next prime is 669965837. The reversal of 669965820 is 28569966.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1331689 + ... + 1332191.

It is an arithmetic number, because the mean of its divisors is an integer number (19897920).

Almost surely, 2^669965820 is an apocalyptic number.

669965820 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 669965820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (955100160).

669965820 is an abundant number, since it is smaller than the sum of its proper divisors (1240234500).

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

669965820 is a wasteful number, since it uses less digits than its factorization.

669965820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 875 (or 873 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 51.

The square root of 669965820 is about 25883.6979583675. The cubic root of 669965820 is about 875.0191320987.

The spelling of 669965820 in words is "six hundred sixty-nine million, nine hundred sixty-five thousand, eight hundred twenty".