31724081 has 2 divisors, whose sum is σ = 31724082. Its totient is φ = 31724080.

The previous prime is 31724071. The next prime is 31724083. The reversal of 31724081 is 18042713.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18879025 + 12845056 = 4345^2 + 3584^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31724081 is a prime.

It is a super-2 number, since 2×31724081² = 2012834630589122, which contains 22 as substring.

Together with 31724083, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31724081.

It is not a weakly prime, because it can be changed into another prime (31724083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15862040 + 15862041.

It is an arithmetic number, because the mean of its divisors is an integer number (15862041).

Almost surely, 2^31724081 is an apocalyptic number.

It is an amenable number.

31724081 is a deficient number, since it is larger than the sum of its proper divisors (1).

31724081 is an equidigital number, since it uses as much as digits as its factorization.

31724081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 31724081 is about 5632.4134258770. The cubic root of 31724081 is about 316.5650873946.

Adding to 31724081 its reverse (18042713), we get a palindrome (49766794).

The spelling of 31724081 in words is "thirty-one million, seven hundred twenty-four thousand, eighty-one".