161616161 has 12 divisors (see below), whose sum is σ = 199062468. Its totient is φ = 130378752.

The previous prime is 161616151. The next prime is 161616179.

161616161 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 144961600 + 16654561 = 12040^2 + 4081^2 .

It is not a de Polignac number, because 161616161 - 2⁶ = 161616097 is a prime.

It is a super-2 number, since 2×161616161² = 52239566992755842, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

161616161 is an undulating number in base 10.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161616151) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 96176 + ... + 97841.

It is an arithmetic number, because the mean of its divisors is an integer number (16588539).

Almost surely, 2^161616161 is an apocalyptic number.

It is an amenable number.

161616161 is a deficient number, since it is larger than the sum of its proper divisors (37446307).

161616161 is a wasteful number, since it uses less digits than its factorization.

161616161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194048 (or 194041 counting only the distinct ones).

The product of its digits is 1296, while the sum is 29.

The square root of 161616161 is about 12712.8344990407. The cubic root of 161616161 is about 544.7052930699.

It can be divided in two parts, 16161 and 6161, that added together give a palindrome (22322).

The spelling of 161616161 in words is "one hundred sixty-one million, six hundred sixteen thousand, one hundred sixty-one".