31497997 has 2 divisors, whose sum is σ = 31497998. Its totient is φ = 31497996.

The previous prime is 31497979. The next prime is 31498003. The reversal of 31497997 is 79979413.

It is a happy number.

Together with previous prime (31497979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15768841 + 15729156 = 3971^2 + 3966^2 .

It is an emirp because it is prime and its reverse (79979413) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31497997 - 2¹¹ = 31495949 is a prime.

It is a super-3 number, since 3×31497997³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31497997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31497797) 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, 15748998 + 15748999.

It is an arithmetic number, because the mean of its divisors is an integer number (15748999).

Almost surely, 2^31497997 is an apocalyptic number.

It is an amenable number.

31497997 is a deficient number, since it is larger than the sum of its proper divisors (1).

31497997 is an equidigital number, since it uses as much as digits as its factorization.

31497997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 428652, while the sum is 49.

The square root of 31497997 is about 5612.3076359017. The cubic root of 31497997 is about 315.8112857366.

The spelling of 31497997 in words is "thirty-one million, four hundred ninety-seven thousand, nine hundred ninety-seven".