166667999 has 2 divisors, whose sum is σ = 166668000. Its totient is φ = 166667998.

The previous prime is 166667953. The next prime is 166668001. The reversal of 166667999 is 999766661.

It is a strong prime.

It is an emirp because it is prime and its reverse (999766661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166667999 is a prime.

It is a Sophie Germain prime.

Together with 166668001, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166667899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83333999 + 83334000.

It is an arithmetic number, because the mean of its divisors is an integer number (83334000).

Almost surely, 2^166667999 is an apocalyptic number.

166667999 is a deficient number, since it is larger than the sum of its proper divisors (1).

166667999 is an equidigital number, since it uses as much as digits as its factorization.

166667999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6613488, while the sum is 59.

The square root of 166667999 is about 12909.9960883030. The cubic root of 166667999 is about 550.3226745678.

The spelling of 166667999 in words is "one hundred sixty-six million, six hundred sixty-seven thousand, nine hundred ninety-nine".