1665040 has 40 divisors (see below), whose sum is σ = 4171608. Its totient is φ = 614400.

The previous prime is 1665029. The next prime is 1665043. The reversal of 1665040 is 405661.

It can be written as a sum of positive squares in 4 ways, for example, as 374544 + 1290496 = 612^2 + 1136^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (1665043) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 240 + ... + 1840.

2^1665040 is an apocalyptic number.

1665040 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 1665040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2085804).

1665040 is an abundant number, since it is smaller than the sum of its proper divisors (2506568).

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

1665040 is a wasteful number, since it uses less digits than its factorization.

1665040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1627 (or 1621 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 1665040 is about 1290.3642896485. The cubic root of 1665040 is about 118.5245250621.

It can be divided in two parts, 16 and 65040, that added together give a palindrome (65056).

The spelling of 1665040 in words is "one million, six hundred sixty-five thousand, forty".