31117081 has 2 divisors, whose sum is σ = 31117082. Its totient is φ = 31117080.

The previous prime is 31117069. The next prime is 31117103. The reversal of 31117081 is 18071113.

It is an a-pointer prime, because the next prime (31117103) can be obtained adding 31117081 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22467600 + 8649481 = 4740^2 + 2941^2 .

It is an emirp because it is prime and its reverse (18071113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31117081 - 2⁵ = 31117049 is a prime.

It is a super-2 number, since 2×31117081² = 1936545459921122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31117001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15558540 + 15558541.

It is an arithmetic number, because the mean of its divisors is an integer number (15558541).

Almost surely, 2^31117081 is an apocalyptic number.

It is an amenable number.

31117081 is a deficient number, since it is larger than the sum of its proper divisors (1).

31117081 is an equidigital number, since it uses as much as digits as its factorization.

31117081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 22.

The square root of 31117081 is about 5578.2686382067. The cubic root of 31117081 is about 314.5330479551.

Adding to 31117081 its reverse (18071113), we get a palindrome (49188194).

The spelling of 31117081 in words is "thirty-one million, one hundred seventeen thousand, eighty-one".