31668281 has 2 divisors, whose sum is σ = 31668282. Its totient is φ = 31668280.

The previous prime is 31668257. The next prime is 31668347. The reversal of 31668281 is 18286613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26419600 + 5248681 = 5140^2 + 2291^2 .

It is an emirp because it is prime and its reverse (18286613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31668281 - 2¹⁰ = 31667257 is a prime.

It is a super-2 number, since 2×31668281² = 2005760042989922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31668251) 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, 15834140 + 15834141.

It is an arithmetic number, because the mean of its divisors is an integer number (15834141).

Almost surely, 2^31668281 is an apocalyptic number.

It is an amenable number.

31668281 is a deficient number, since it is larger than the sum of its proper divisors (1).

31668281 is an equidigital number, since it uses as much as digits as its factorization.

31668281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 35.

The square root of 31668281 is about 5627.4577741641. The cubic root of 31668281 is about 316.3793746474.

The spelling of 31668281 in words is "thirty-one million, six hundred sixty-eight thousand, two hundred eighty-one".