166691439 has 12 divisors (see below), whose sum is σ = 249694536. Its totient is φ = 111127464.

The previous prime is 166691431. The next prime is 166691531. The reversal of 166691439 is 934196661.

It is not a de Polignac number, because 166691439 - 2³ = 166691431 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 166691394 and 166691403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166691431) 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 in 11 ways as a sum of consecutive naturals, for example, 342744 + ... + 343229.

It is an arithmetic number, because the mean of its divisors is an integer number (20807878).

Almost surely, 2^166691439 is an apocalyptic number.

166691439 is a deficient number, since it is larger than the sum of its proper divisors (83003097).

166691439 is an frugal number, since it uses more digits than its factorization.

166691439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685988 (or 685976 counting only the distinct ones).

The product of its digits is 209952, while the sum is 45.

The square root of 166691439 is about 12910.9038800543. The cubic root of 166691439 is about 550.3484722792.

The spelling of 166691439 in words is "one hundred sixty-six million, six hundred ninety-one thousand, four hundred thirty-nine".