31221413 has 2 divisors, whose sum is σ = 31221414. Its totient is φ = 31221412.

The previous prime is 31221403. The next prime is 31221431. The reversal of 31221413 is 31412213.

Together with next prime (31221431) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19918369 + 11303044 = 4463^2 + 3362^2 .

It is a cyclic number.

It is not a de Polignac number, because 31221413 - 2¹⁴ = 31205029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31221391 and 31221400.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31221403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15610706 + 15610707.

It is an arithmetic number, because the mean of its divisors is an integer number (15610707).

Almost surely, 2^31221413 is an apocalyptic number.

It is an amenable number.

31221413 is a deficient number, since it is larger than the sum of its proper divisors (1).

31221413 is an equidigital number, since it uses as much as digits as its factorization.

31221413 is an evil number, because the sum of its binary digits is even.

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

The square root of 31221413 is about 5587.6124597184. The cubic root of 31221413 is about 314.8841868701.

Adding to 31221413 its reverse (31412213), we get a palindrome (62633626).

The spelling of 31221413 in words is "thirty-one million, two hundred twenty-one thousand, four hundred thirteen".