166978739 has 2 divisors, whose sum is σ = 166978740. Its totient is φ = 166978738.

The previous prime is 166978727. The next prime is 166978753. The reversal of 166978739 is 937879661.

It is a weak prime.

It is an emirp because it is prime and its reverse (937879661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166978739 is a prime.

It is not a weakly prime, because it can be changed into another prime (166978039) 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, 83489369 + 83489370.

It is an arithmetic number, because the mean of its divisors is an integer number (83489370).

Almost surely, 2^166978739 is an apocalyptic number.

166978739 is a deficient number, since it is larger than the sum of its proper divisors (1).

166978739 is an equidigital number, since it uses as much as digits as its factorization.

166978739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3429216, while the sum is 56.

The square root of 166978739 is about 12922.0253443491. The cubic root of 166978739 is about 550.6644740376.

It can be divided in two parts, 1669 and 78739, that added together give a palindrome (80408).

The spelling of 166978739 in words is "one hundred sixty-six million, nine hundred seventy-eight thousand, seven hundred thirty-nine".