669391920 has 120 divisors (see below), whose sum is σ = 2325632400. Its totient is φ = 172343808.

The previous prime is 669391913. The next prime is 669391939. The reversal of 669391920 is 29193966.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×669391920² = 896171085122572800, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4851 + ... + 36909.

It is an arithmetic number, because the mean of its divisors is an integer number (19380270).

Almost surely, 2^669391920 is an apocalyptic number.

669391920 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 669391920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1162816200).

669391920 is an abundant number, since it is smaller than the sum of its proper divisors (1656240480).

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

669391920 is a wasteful number, since it uses less digits than its factorization.

669391920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32107 (or 32098 counting only the distinct ones).

The product of its (nonzero) digits is 157464, while the sum is 45.

The square root of 669391920 is about 25872.6094547883. The cubic root of 669391920 is about 874.7692104249.

The spelling of 669391920 in words is "six hundred sixty-nine million, three hundred ninety-one thousand, nine hundred twenty".