166539791 has 16 divisors (see below), whose sum is σ = 185481888. Its totient is φ = 148262400.

The previous prime is 166539761. The next prime is 166539797. The reversal of 166539791 is 197935661.

It is a happy number.

It is not a de Polignac number, because 166539791 - 2¹⁰ = 166538767 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166539797) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 125411 + ... + 126731.

It is an arithmetic number, because the mean of its divisors is an integer number (11592618).

Almost surely, 2^166539791 is an apocalyptic number.

166539791 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

166539791 is a deficient number, since it is larger than the sum of its proper divisors (18942097).

166539791 is a wasteful number, since it uses less digits than its factorization.

166539791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1562.

The product of its digits is 306180, while the sum is 47.

The square root of 166539791 is about 12905.0296783851. The cubic root of 166539791 is about 550.1815279587.

The spelling of 166539791 in words is "one hundred sixty-six million, five hundred thirty-nine thousand, seven hundred ninety-one".