161791851 has 16 divisors (see below), whose sum is σ = 232708896. Its totient is φ = 99396096.

The previous prime is 161791823. The next prime is 161791901. The reversal of 161791851 is 158197161.

It is not a de Polignac number, because 161791851 - 2¹³ = 161783659 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (161791051) 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 15 ways as a sum of consecutive naturals, for example, 22291 + ... + 28643.

It is an arithmetic number, because the mean of its divisors is an integer number (14544306).

Almost surely, 2^161791851 is an apocalyptic number.

161791851 is a deficient number, since it is larger than the sum of its proper divisors (70917045).

161791851 is a wasteful number, since it uses less digits than its factorization.

161791851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7022.

The product of its digits is 15120, while the sum is 39.

The square root of 161791851 is about 12719.7425681497. The cubic root of 161791851 is about 544.9026013416.

The spelling of 161791851 in words is "one hundred sixty-one million, seven hundred ninety-one thousand, eight hundred fifty-one".