166861979 has 2 divisors, whose sum is σ = 166861980. Its totient is φ = 166861978.

The previous prime is 166861963. The next prime is 166861991. The reversal of 166861979 is 979168661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 166861979 - 2⁴ = 166861963 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166861979.

It is not a weakly prime, because it can be changed into another prime (166860979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83430989 + 83430990.

It is an arithmetic number, because the mean of its divisors is an integer number (83430990).

Almost surely, 2^166861979 is an apocalyptic number.

166861979 is a deficient number, since it is larger than the sum of its proper divisors (1).

166861979 is an equidigital number, since it uses as much as digits as its factorization.

166861979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 53.

The square root of 166861979 is about 12917.5066866636. The cubic root of 166861979 is about 550.5360932700.

The spelling of 166861979 in words is "one hundred sixty-six million, eight hundred sixty-one thousand, nine hundred seventy-nine".