166639405249 has 2 divisors, whose sum is σ = 166639405250. Its totient is φ = 166639405248.

The previous prime is 166639405211. The next prime is 166639405253. The reversal of 166639405249 is 942504936661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154020927025 + 12618478224 = 392455^2 + 112332^2 .

It is a cyclic number.

It is not a de Polignac number, because 166639405249 - 2¹⁵ = 166639372481 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166639405249.

It is not a weakly prime, because it can be changed into another prime (166639445249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83319702624 + 83319702625.

It is an arithmetic number, because the mean of its divisors is an integer number (83319702625).

Almost surely, 2^166639405249 is an apocalyptic number.

It is an amenable number.

166639405249 is a deficient number, since it is larger than the sum of its proper divisors (1).

166639405249 is an equidigital number, since it uses as much as digits as its factorization.

166639405249 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8398080, while the sum is 55.

The spelling of 166639405249 in words is "one hundred sixty-six billion, six hundred thirty-nine million, four hundred five thousand, two hundred forty-nine".