166917187949 has 2 divisors, whose sum is σ = 166917187950. Its totient is φ = 166917187948.

The previous prime is 166917187903. The next prime is 166917188027. The reversal of 166917187949 is 949781719661.

It is a happy number.

166917187949 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111084223849 + 55832964100 = 333293^2 + 236290^2 .

It is an emirp because it is prime and its reverse (949781719661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 166917187949 - 2¹⁶ = 166917122413 is a prime.

It is a super-2 number, since 2×166917187949² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166917187049) 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, 83458593974 + 83458593975.

It is an arithmetic number, because the mean of its divisors is an integer number (83458593975).

Almost surely, 2^166917187949 is an apocalyptic number.

It is an amenable number.

166917187949 is a deficient number, since it is larger than the sum of its proper divisors (1).

166917187949 is an equidigital number, since it uses as much as digits as its factorization.

166917187949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41150592, while the sum is 68.

The spelling of 166917187949 in words is "one hundred sixty-six billion, nine hundred seventeen million, one hundred eighty-seven thousand, nine hundred forty-nine".