31421213 has 2 divisors, whose sum is σ = 31421214. Its totient is φ = 31421212.

The previous prime is 31421189. The next prime is 31421233. The reversal of 31421213 is 31212413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31382404 + 38809 = 5602^2 + 197^2 .

It is an emirp because it is prime and its reverse (31212413) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31421213 - 2¹⁰ = 31420189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31421191 and 31421200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31421233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15710606 + 15710607.

It is an arithmetic number, because the mean of its divisors is an integer number (15710607).

Almost surely, 2^31421213 is an apocalyptic number.

It is an amenable number.

31421213 is a deficient number, since it is larger than the sum of its proper divisors (1).

31421213 is an equidigital number, since it uses as much as digits as its factorization.

31421213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 17.

The square root of 31421213 is about 5605.4627819655. The cubic root of 31421213 is about 315.5544547496.

Adding to 31421213 its reverse (31212413), we get a palindrome (62633626).

The spelling of 31421213 in words is "thirty-one million, four hundred twenty-one thousand, two hundred thirteen".