166821269 has 2 divisors, whose sum is σ = 166821270. Its totient is φ = 166821268.

The previous prime is 166821247. The next prime is 166821313. The reversal of 166821269 is 962128661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159719044 + 7102225 = 12638^2 + 2665^2 .

It is a cyclic number.

It is not a de Polignac number, because 166821269 - 2²⁰ = 165772693 is a prime.

It is a super-2 number, since 2×166821269² = 55658671581540722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166821569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83410634 + 83410635.

It is an arithmetic number, because the mean of its divisors is an integer number (83410635).

Almost surely, 2^166821269 is an apocalyptic number.

It is an amenable number.

166821269 is a deficient number, since it is larger than the sum of its proper divisors (1).

166821269 is an equidigital number, since it uses as much as digits as its factorization.

166821269 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 41.

The square root of 166821269 is about 12915.9308220507. The cubic root of 166821269 is about 550.4913174471.

The spelling of 166821269 in words is "one hundred sixty-six million, eight hundred twenty-one thousand, two hundred sixty-nine".