161105631 has 4 divisors (see below), whose sum is σ = 214807512. Its totient is φ = 107403752.

The previous prime is 161105629. The next prime is 161105641. The reversal of 161105631 is 136501161.

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

It is a cyclic number.

It is not a de Polignac number, because 161105631 - 2¹ = 161105629 is a prime.

It is a super-2 number, since 2×161105631² = 51910048679816322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161105641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26850936 + ... + 26850941.

It is an arithmetic number, because the mean of its divisors is an integer number (53701878).

Almost surely, 2^161105631 is an apocalyptic number.

161105631 is a deficient number, since it is larger than the sum of its proper divisors (53701881).

161105631 is an equidigital number, since it uses as much as digits as its factorization.

161105631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53701880.

The product of its (nonzero) digits is 540, while the sum is 24.

The square root of 161105631 is about 12692.7393024516. The cubic root of 161105631 is about 544.1311307569.

Adding to 161105631 its reverse (136501161), we get a palindrome (297606792).

The spelling of 161105631 in words is "one hundred sixty-one million, one hundred five thousand, six hundred thirty-one".