31686349 has 2 divisors, whose sum is σ = 31686350. Its totient is φ = 31686348.

The previous prime is 31686289. The next prime is 31686353. The reversal of 31686349 is 94368613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24700900 + 6985449 = 4970^2 + 2643^2 .

It is a cyclic number.

It is not a de Polignac number, because 31686349 - 2⁹ = 31685837 is a prime.

It is a nialpdrome in base 9.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31686359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15843174 + 15843175.

It is an arithmetic number, because the mean of its divisors is an integer number (15843175).

Almost surely, 2^31686349 is an apocalyptic number.

It is an amenable number.

31686349 is a deficient number, since it is larger than the sum of its proper divisors (1).

31686349 is an equidigital number, since it uses as much as digits as its factorization.

31686349 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 40.

The square root of 31686349 is about 5629.0628882612. The cubic root of 31686349 is about 316.4395321675.

The spelling of 31686349 in words is "thirty-one million, six hundred eighty-six thousand, three hundred forty-nine".