669440 has 36 divisors (see below), whose sum is σ = 1606584. Its totient is φ = 267264.

The previous prime is 669437. The next prime is 669451. The reversal of 669440 is 44966.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1019 + ... + 1541.

2⁶⁶⁹⁴⁴⁰ 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 669440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (803292).

669440 is an abundant number, since it is smaller than the sum of its proper divisors (937144).

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

669440 is an equidigital number, since it uses as much as digits as its factorization.

669440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544 (or 530 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 669440 is about 818.1931312349. The cubic root of 669440 is about 87.4790153759.

The spelling of 669440 in words is "six hundred sixty-nine thousand, four hundred forty".