31020212221 has 4 divisors (see below), whose sum is σ = 31027310172. Its totient is φ = 31013114272.

The previous prime is 31020212207. The next prime is 31020212233. The reversal of 31020212221 is 12221202013.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13033647225 + 17986564996 = 114165^2 + 134114^2 .

It is a cyclic number.

It is not a de Polignac number, because 31020212221 - 2¹¹ = 31020210173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31020212195 and 31020212204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31020212621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3542416 + ... + 3551161.

It is an arithmetic number, because the mean of its divisors is an integer number (7756827543).

Almost surely, 2^31020212221 is an apocalyptic number.

It is an amenable number.

31020212221 is a deficient number, since it is larger than the sum of its proper divisors (7097951).

31020212221 is an equidigital number, since it uses as much as digits as its factorization.

31020212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7097950.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 31020212221 its reverse (12221202013), we get a palindrome (43241414234).

The spelling of 31020212221 in words is "thirty-one billion, twenty million, two hundred twelve thousand, two hundred twenty-one".