161139785 has 4 divisors (see below), whose sum is σ = 193367748. Its totient is φ = 128911824.

The previous prime is 161139763. The next prime is 161139793. The reversal of 161139785 is 587931161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 110103049 + 51036736 = 10493^2 + 7144^2 .

It is a cyclic number.

It is not a de Polignac number, because 161139785 - 2⁶ = 161139721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16113974 + ... + 16113983.

It is an arithmetic number, because the mean of its divisors is an integer number (48341937).

Almost surely, 2^161139785 is an apocalyptic number.

It is an amenable number.

161139785 is a deficient number, since it is larger than the sum of its proper divisors (32227963).

161139785 is an equidigital number, since it uses as much as digits as its factorization.

161139785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32227962.

The product of its digits is 45360, while the sum is 41.

The square root of 161139785 is about 12694.0846460074. The cubic root of 161139785 is about 544.1695795300.

The spelling of 161139785 in words is "one hundred sixty-one million, one hundred thirty-nine thousand, seven hundred eighty-five".