31981073 has 2 divisors, whose sum is σ = 31981074. Its totient is φ = 31981072.

The previous prime is 31981067. The next prime is 31981087. The reversal of 31981073 is 37018913.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22202944 + 9778129 = 4712^2 + 3127^2 .

It is a cyclic number.

It is not a de Polignac number, because 31981073 - 2¹⁰ = 31980049 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31941073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15990536 + 15990537.

It is an arithmetic number, because the mean of its divisors is an integer number (15990537).

Almost surely, 2^31981073 is an apocalyptic number.

It is an amenable number.

31981073 is a deficient number, since it is larger than the sum of its proper divisors (1).

31981073 is an equidigital number, since it uses as much as digits as its factorization.

31981073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 31981073 is about 5655.1810757924. The cubic root of 31981073 is about 317.4176048412.

Adding to 31981073 its reverse (37018913), we get a palindrome (68999986).

The spelling of 31981073 in words is "thirty-one million, nine hundred eighty-one thousand, seventy-three".