1664440 has 16 divisors (see below), whose sum is σ = 3745080. Its totient is φ = 665760.

The previous prime is 1664437. The next prime is 1664447. The reversal of 1664440 is 444661.

1664440 = 315² + 316² + ... + 330².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20766 + ... + 20845.

2^1664440 is an apocalyptic number.

1664440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664440 is an abundant number, since it is smaller than the sum of its proper divisors (2080640).

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

1664440 is a wasteful number, since it uses less digits than its factorization.

1664440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41622 (or 41618 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 1664440 is about 1290.1317762151. The cubic root of 1664440 is about 118.5102865135.

The spelling of 1664440 in words is "one million, six hundred sixty-four thousand, four hundred forty".