161081785 has 8 divisors (see below), whose sum is σ = 196467336. Its totient is φ = 126752640.

The previous prime is 161081779. The next prime is 161081801. The reversal of 161081785 is 587180161.

It can be written as a sum of positive squares in 4 ways, for example, as 2019241 + 159062544 = 1421^2 + 12612^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161081785 - 2¹⁹ = 160557497 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 263764 + ... + 264373.

It is an arithmetic number, because the mean of its divisors is an integer number (24558417).

Almost surely, 2^161081785 is an apocalyptic number.

It is an amenable number.

161081785 is a deficient number, since it is larger than the sum of its proper divisors (35385551).

161081785 is an equidigital number, since it uses as much as digits as its factorization.

161081785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528203.

The product of its (nonzero) digits is 13440, while the sum is 37.

The square root of 161081785 is about 12691.7999117540. The cubic root of 161081785 is about 544.1042829654.

It can be divided in two parts, 16 and 1081785, that added together give a palindrome (1081801).

The spelling of 161081785 in words is "one hundred sixty-one million, eighty-one thousand, seven hundred eighty-five".