166317881 has 2 divisors, whose sum is σ = 166317882. Its totient is φ = 166317880.

The previous prime is 166317859. The next prime is 166317889. The reversal of 166317881 is 188713661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128618281 + 37699600 = 11341^2 + 6140^2 .

It is an emirp because it is prime and its reverse (188713661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166317881 is a prime.

It is a super-2 number, since 2×166317881² = 55323275080660322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (166317889) 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, 83158940 + 83158941.

It is an arithmetic number, because the mean of its divisors is an integer number (83158941).

Almost surely, 2^166317881 is an apocalyptic number.

It is an amenable number.

166317881 is a deficient number, since it is larger than the sum of its proper divisors (1).

166317881 is an equidigital number, since it uses as much as digits as its factorization.

166317881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 41.

The square root of 166317881 is about 12896.4290018594. The cubic root of 166317881 is about 549.9370517489.

The spelling of 166317881 in words is "one hundred sixty-six million, three hundred seventeen thousand, eight hundred eighty-one".