164213681 has 2 divisors, whose sum is σ = 164213682. Its totient is φ = 164213680.

The previous prime is 164213669. The next prime is 164213683. The reversal of 164213681 is 186312461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137007025 + 27206656 = 11705^2 + 5216^2 .

It is a cyclic number.

It is not a de Polignac number, because 164213681 - 2¹⁸ = 163951537 is a prime.

It is a super-2 number, since 2×164213681² = 53932266055139522, which contains 22 as substring.

Together with 164213683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (164213683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82106840 + 82106841.

It is an arithmetic number, because the mean of its divisors is an integer number (82106841).

Almost surely, 2^164213681 is an apocalyptic number.

It is an amenable number.

164213681 is a deficient number, since it is larger than the sum of its proper divisors (1).

164213681 is an equidigital number, since it uses as much as digits as its factorization.

164213681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 164213681 is about 12814.5886004975. The cubic root of 164213681 is about 547.6079932645.

It can be divided in two parts, 16421 and 3681, that added together give a palindrome (20102).

The spelling of 164213681 in words is "one hundred sixty-four million, two hundred thirteen thousand, six hundred eighty-one".