31431161 has 2 divisors, whose sum is σ = 31431162. Its totient is φ = 31431160.

The previous prime is 31431139. The next prime is 31431163. The reversal of 31431161 is 16113413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18757561 + 12673600 = 4331^2 + 3560^2 .

It is a cyclic number.

It is not a de Polignac number, because 31431161 - 2¹⁴ = 31414777 is a prime.

Together with 31431163, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31431163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15715580 + 15715581.

It is an arithmetic number, because the mean of its divisors is an integer number (15715581).

Almost surely, 2^31431161 is an apocalyptic number.

It is an amenable number.

31431161 is a deficient number, since it is larger than the sum of its proper divisors (1).

31431161 is an equidigital number, since it uses as much as digits as its factorization.

31431161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216, while the sum is 20.

The square root of 31431161 is about 5606.3500604226. The cubic root of 31431161 is about 315.5877528964.

Adding to 31431161 its reverse (16113413), we get a palindrome (47544574).

The spelling of 31431161 in words is "thirty-one million, four hundred thirty-one thousand, one hundred sixty-one".