669408 has 48 divisors (see below), whose sum is σ = 1854720. Its totient is φ = 210816.

The previous prime is 669401. The next prime is 669413. The reversal of 669408 is 804966.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1641 + ... + 2007.

It is an arithmetic number, because the mean of its divisors is an integer number (38640).

2⁶⁶⁹⁴⁰⁸ 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 669408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (927360).

669408 is an abundant number, since it is smaller than the sum of its proper divisors (1185312).

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

669408 is a wasteful number, since it uses less digits than its factorization.

669408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 669408 is about 818.1735757161. The cubic root of 669408 is about 87.4776214880.

The spelling of 669408 in words is "six hundred sixty-nine thousand, four hundred eight".