1669640 has 64 divisors (see below), whose sum is σ = 4406400. Its totient is φ = 557568.

The previous prime is 1669637. The next prime is 1669649. The reversal of 1669640 is 469661.

It is a junction number, because it is equal to n+sod(n) for n = 1669597 and 1669606.

It is not an unprimeable number, because it can be changed into a prime (1669649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18716 + ... + 18804.

It is an arithmetic number, because the mean of its divisors is an integer number (68850).

2^1669640 is an apocalyptic number.

1669640 is a gapful number since it is divisible by the number (10) 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 1669640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2203200).

1669640 is an abundant number, since it is smaller than the sum of its proper divisors (2736760).

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

1669640 is a wasteful number, since it uses less digits than its factorization.

1669640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 1669640 is about 1292.1455026428. The cubic root of 1669640 is about 118.6335737934.

The spelling of 1669640 in words is "one million, six hundred sixty-nine thousand, six hundred forty".