1664225 has 6 divisors (see below), whose sum is σ = 2063670. Its totient is φ = 1331360.

The previous prime is 1664123. The next prime is 1664227. The reversal of 1664225 is 5224661.

It can be written as a sum of positive squares in 3 ways, for example, as 2704 + 1661521 = 52^2 + 1289^2 .

It is not a de Polignac number, because 1664225 - 2¹⁶ = 1598689 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 1664194 and 1664203.

It is not an unprimeable number, because it can be changed into a prime (1664227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 33260 + ... + 33309.

It is an arithmetic number, because the mean of its divisors is an integer number (343945).

2^1664225 is an apocalyptic number.

It is an amenable number.

1664225 is a deficient number, since it is larger than the sum of its proper divisors (399445).

1664225 is an equidigital number, since it uses as much as digits as its factorization.

1664225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66579 (or 66574 counting only the distinct ones).

The product of its digits is 2880, while the sum is 26.

The square root of 1664225 is about 1290.0484487026. The cubic root of 1664225 is about 118.5051835342.

Adding to 1664225 its reverse (5224661), we get a palindrome (6888886).

The spelling of 1664225 in words is "one million, six hundred sixty-four thousand, two hundred twenty-five".