31281973 has 2 divisors, whose sum is σ = 31281974. Its totient is φ = 31281972.

The previous prime is 31281967. The next prime is 31281997. The reversal of 31281973 is 37918213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31281649 + 324 = 5593^2 + 18^2 .

It is an emirp because it is prime and its reverse (37918213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31281973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31281473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15640986 + 15640987.

It is an arithmetic number, because the mean of its divisors is an integer number (15640987).

Almost surely, 2^31281973 is an apocalyptic number.

It is an amenable number.

31281973 is a deficient number, since it is larger than the sum of its proper divisors (1).

31281973 is an equidigital number, since it uses as much as digits as its factorization.

31281973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 34.

The square root of 31281973 is about 5593.0289647024. The cubic root of 31281973 is about 315.0876484072.

The spelling of 31281973 in words is "thirty-one million, two hundred eighty-one thousand, nine hundred seventy-three".