31818161 has 2 divisors, whose sum is σ = 31818162. Its totient is φ = 31818160.

The previous prime is 31818109. The next prime is 31818181. The reversal of 31818161 is 16181813.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22090000 + 9728161 = 4700^2 + 3119^2 .

It is a cyclic number.

It is not a de Polignac number, because 31818161 - 2⁶ = 31818097 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31818181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15909080 + 15909081.

It is an arithmetic number, because the mean of its divisors is an integer number (15909081).

Almost surely, 2^31818161 is an apocalyptic number.

It is an amenable number.

31818161 is a deficient number, since it is larger than the sum of its proper divisors (1).

31818161 is an equidigital number, since it uses as much as digits as its factorization.

31818161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 29.

The square root of 31818161 is about 5640.7589028428. The cubic root of 31818161 is about 316.8777105949.

Adding to 31818161 its reverse (16181813), we get a palindrome (47999974).

The spelling of 31818161 in words is "thirty-one million, eight hundred eighteen thousand, one hundred sixty-one".