166399481 has 2 divisors, whose sum is σ = 166399482. Its totient is φ = 166399480.

The previous prime is 166399469. The next prime is 166399483. The reversal of 166399481 is 184993661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105247081 + 61152400 = 10259^2 + 7820^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166399481 is a prime.

It is a super-2 number, since 2×166399481² = 55377574554138722, which contains 22 as substring.

Together with 166399483, 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 (166399483) 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, 83199740 + 83199741.

It is an arithmetic number, because the mean of its divisors is an integer number (83199741).

Almost surely, 2^166399481 is an apocalyptic number.

It is an amenable number.

166399481 is a deficient number, since it is larger than the sum of its proper divisors (1).

166399481 is an equidigital number, since it uses as much as digits as its factorization.

166399481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 47.

The square root of 166399481 is about 12899.5922803785. The cubic root of 166399481 is about 550.0269749855.

The spelling of 166399481 in words is "one hundred sixty-six million, three hundred ninety-nine thousand, four hundred eighty-one".