1664280 has 128 divisors (see below), whose sum is σ = 5875200. Its totient is φ = 418176.

The previous prime is 1664279. The next prime is 1664287. The reversal of 1664280 is 824661.

1664280 is a `hidden beast` number, since 16 + 642 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664287) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24807 + ... + 24873.

It is an arithmetic number, because the mean of its divisors is an integer number (45900).

2^1664280 is an apocalyptic number.

1664280 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 1664280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2937600).

1664280 is an abundant number, since it is smaller than the sum of its proper divisors (4210920).

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

1664280 is a wasteful number, since it uses less digits than its factorization.

1664280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1664280 is about 1290.0697655553. The cubic root of 1664280 is about 118.5064889893.

The spelling of 1664280 in words is "one million, six hundred sixty-four thousand, two hundred eighty".