31521671 has 2 divisors, whose sum is σ = 31521672. Its totient is φ = 31521670.

The previous prime is 31521667. The next prime is 31521673. The reversal of 31521671 is 17612513.

It is a strong prime.

It is an emirp because it is prime and its reverse (17612513) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31521671 - 2² = 31521667 is a prime.

Together with 31521673, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31521671.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31521673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15760835 + 15760836.

It is an arithmetic number, because the mean of its divisors is an integer number (15760836).

Almost surely, 2^31521671 is an apocalyptic number.

31521671 is a deficient number, since it is larger than the sum of its proper divisors (1).

31521671 is an equidigital number, since it uses as much as digits as its factorization.

31521671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1260, while the sum is 26.

The square root of 31521671 is about 5614.4163543506. The cubic root of 31521671 is about 315.8903875287.

The spelling of 31521671 in words is "thirty-one million, five hundred twenty-one thousand, six hundred seventy-one".