164640521 has 2 divisors, whose sum is σ = 164640522. Its totient is φ = 164640520.

The previous prime is 164640517. The next prime is 164640533. The reversal of 164640521 is 125046461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 124634896 + 40005625 = 11164^2 + 6325^2 .

It is a cyclic number.

It is not a de Polignac number, because 164640521 - 2² = 164640517 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (164640571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82320260 + 82320261.

It is an arithmetic number, because the mean of its divisors is an integer number (82320261).

Almost surely, 2^164640521 is an apocalyptic number.

It is an amenable number.

164640521 is a deficient number, since it is larger than the sum of its proper divisors (1).

164640521 is an equidigital number, since it uses as much as digits as its factorization.

164640521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 164640521 is about 12831.2322479176. The cubic root of 164640521 is about 548.0820478940.

Adding to 164640521 its reverse (125046461), we get a palindrome (289686982).

The spelling of 164640521 in words is "one hundred sixty-four million, six hundred forty thousand, five hundred twenty-one".