31243013 has 2 divisors, whose sum is σ = 31243014. Its totient is φ = 31243012.

The previous prime is 31243007. The next prime is 31243061. The reversal of 31243013 is 31034213.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30891364 + 351649 = 5558^2 + 593^2 .

It is a cyclic number.

It is not a de Polignac number, because 31243013 - 2⁶ = 31242949 is a prime.

It is a super-2 number, since 2×31243013² = 1952251722636338, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31242982 and 31243000.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31243073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15621506 + 15621507.

It is an arithmetic number, because the mean of its divisors is an integer number (15621507).

Almost surely, 2^31243013 is an apocalyptic number.

It is an amenable number.

31243013 is a deficient number, since it is larger than the sum of its proper divisors (1).

31243013 is an equidigital number, since it uses as much as digits as its factorization.

31243013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 31243013 is about 5589.5449725358. The cubic root of 31243013 is about 314.9567858750.

Adding to 31243013 its reverse (31034213), we get a palindrome (62277226).

The spelling of 31243013 in words is "thirty-one million, two hundred forty-three thousand, thirteen".