1664240 has 40 divisors (see below), whose sum is σ = 3937248. Its totient is φ = 654080.

The previous prime is 1664227. The next prime is 1664251. The reversal of 1664240 is 424661.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5534 + ... + 5826.

2^1664240 is an apocalyptic number.

1664240 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 1664240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1968624).

1664240 is an abundant number, since it is smaller than the sum of its proper divisors (2273008).

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

1664240 is a wasteful number, since it uses less digits than its factorization.

1664240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 1664240 is about 1290.0542624246. The cubic root of 1664240 is about 118.5055395702.

The spelling of 1664240 in words is "one million, six hundred sixty-four thousand, two hundred forty".