166221929 has 2 divisors, whose sum is σ = 166221930. Its totient is φ = 166221928.

The previous prime is 166221919. The next prime is 166221931. The reversal of 166221929 is 929122661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 164531929 + 1690000 = 12827^2 + 1300^2 .

It is a cyclic number.

It is not a de Polignac number, because 166221929 - 2⁸ = 166221673 is a prime.

Together with 166221931, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 166221892 and 166221901.

It is not a weakly prime, because it can be changed into another prime (166221919) 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, 83110964 + 83110965.

It is an arithmetic number, because the mean of its divisors is an integer number (83110965).

Almost surely, 2^166221929 is an apocalyptic number.

It is an amenable number.

166221929 is a deficient number, since it is larger than the sum of its proper divisors (1).

166221929 is an equidigital number, since it uses as much as digits as its factorization.

166221929 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 38.

The square root of 166221929 is about 12892.7083655840. The cubic root of 166221929 is about 549.8312749668.

The spelling of 166221929 in words is "one hundred sixty-six million, two hundred twenty-one thousand, nine hundred twenty-nine".