1664320 has 56 divisors (see below), whose sum is σ = 4535424. Its totient is φ = 569856.

The previous prime is 1664291. The next prime is 1664353. The reversal of 1664320 is 234661.

It is a tau number, because it is divible by the number of its divisors (56).

It is a super-2 number, since 2×1664320² = 5539922124800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1664291 and 1664300.

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, 1869 + ... + 2611.

2^1664320 is an apocalyptic number.

1664320 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 1664320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2267712).

1664320 is an abundant number, since it is smaller than the sum of its proper divisors (2871104).

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

1664320 is an equidigital number, since it uses as much as digits as its factorization.

1664320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767 (or 757 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 1664320 is about 1290.0852684997. The cubic root of 1664320 is about 118.5074383932.

Adding to 1664320 its reverse (234661), we get a palindrome (1898981).

The spelling of 1664320 in words is "one million, six hundred sixty-four thousand, three hundred twenty".