31681229 has 2 divisors, whose sum is σ = 31681230. Its totient is φ = 31681228.

The previous prime is 31681219. The next prime is 31681231. The reversal of 31681229 is 92218613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23785129 + 7896100 = 4877^2 + 2810^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31681229 is a prime.

Together with 31681231, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31681195 and 31681204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31681219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15840614 + 15840615.

It is an arithmetic number, because the mean of its divisors is an integer number (15840615).

Almost surely, 2^31681229 is an apocalyptic number.

It is an amenable number.

31681229 is a deficient number, since it is larger than the sum of its proper divisors (1).

31681229 is an equidigital number, since it uses as much as digits as its factorization.

31681229 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 32.

The square root of 31681229 is about 5628.6080872628. The cubic root of 31681229 is about 316.4224874177.

The spelling of 31681229 in words is "thirty-one million, six hundred eighty-one thousand, two hundred twenty-nine".