31697189 has 2 divisors, whose sum is σ = 31697190. Its totient is φ = 31697188.

The previous prime is 31697179. The next prime is 31697191. The reversal of 31697189 is 98179613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31696900 + 289 = 5630^2 + 17^2 .

It is a cyclic number.

It is not a de Polignac number, because 31697189 - 2⁴ = 31697173 is a prime.

Together with 31697191, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31697179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15848594 + 15848595.

It is an arithmetic number, because the mean of its divisors is an integer number (15848595).

Almost surely, 2^31697189 is an apocalyptic number.

It is an amenable number.

31697189 is a deficient number, since it is larger than the sum of its proper divisors (1).

31697189 is an equidigital number, since it uses as much as digits as its factorization.

31697189 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The square root of 31697189 is about 5630.0256660161. The cubic root of 31697189 is about 316.4756130410.

The spelling of 31697189 in words is "thirty-one million, six hundred ninety-seven thousand, one hundred eighty-nine".