164531221 has 2 divisors, whose sum is σ = 164531222. Its totient is φ = 164531220.

The previous prime is 164531183. The next prime is 164531243. The reversal of 164531221 is 122135461.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154380625 + 10150596 = 12425^2 + 3186^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-164531221 is a prime.

It is equal to p_9214207 and since 164531221 and 9214207 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164531021) by changing a digit.

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 as a sum of consecutive naturals, namely, 82265610 + 82265611.

It is an arithmetic number, because the mean of its divisors is an integer number (82265611).

Almost surely, 2^164531221 is an apocalyptic number.

It is an amenable number.

164531221 is a deficient number, since it is larger than the sum of its proper divisors (1).

164531221 is an equidigital number, since it uses as much as digits as its factorization.

164531221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 164531221 is about 12826.9724019349. The cubic root of 164531221 is about 547.9607358605.

Adding to 164531221 its reverse (122135461), we get a palindrome (286666682).

The spelling of 164531221 in words is "one hundred sixty-four million, five hundred thirty-one thousand, two hundred twenty-one".