31221222221 has 8 divisors (see below), whose sum is σ = 35941846080. Its totient is φ = 26565710688.

The previous prime is 31221222209. The next prime is 31221222223. The reversal of 31221222221 is 12222212213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31221222221 - 2¹⁴ = 31221205837 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31221222193 and 31221222202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31221222223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16277051 + ... + 16278968.

It is an arithmetic number, because the mean of its divisors is an integer number (4492730760).

Almost surely, 2^31221222221 is an apocalyptic number.

It is an amenable number.

31221222221 is a deficient number, since it is larger than the sum of its proper divisors (4720623859).

31221222221 is a wasteful number, since it uses less digits than its factorization.

31221222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32556163.

The product of its digits is 384, while the sum is 20.

Adding to 31221222221 its reverse (12222212213), we get a palindrome (43443434434).

It can be divided in two parts, 312212 and 22221, that added together give a palindrome (334433).

The spelling of 31221222221 in words is "thirty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred twenty-one".