164640425 has 6 divisors (see below), whose sum is σ = 204154158. Its totient is φ = 131712320.

The previous prime is 164640397. The next prime is 164640431. The reversal of 164640425 is 524046461.

It can be written as a sum of positive squares in 3 ways, for example, as 49378729 + 115261696 = 7027^2 + 10736^2 .

It is a de Polignac number, because none of the positive numbers 2^k-164640425 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 164640391 and 164640400.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3292784 + ... + 3292833.

It is an arithmetic number, because the mean of its divisors is an integer number (34025693).

Almost surely, 2^164640425 is an apocalyptic number.

It is an amenable number.

164640425 is a deficient number, since it is larger than the sum of its proper divisors (39513733).

164640425 is an equidigital number, since it uses as much as digits as its factorization.

164640425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6585627 (or 6585622 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

The square root of 164640425 is about 12831.2285070448. The cubic root of 164640425 is about 548.0819413672.

Adding to 164640425 its reverse (524046461), we get a palindrome (688686886).

The spelling of 164640425 in words is "one hundred sixty-four million, six hundred forty thousand, four hundred twenty-five".