31213223221 has 8 divisors (see below), whose sum is σ = 31529875104. Its totient is φ = 30898098000.

The previous prime is 31213223147. The next prime is 31213223231. The reversal of 31213223221 is 12232231213.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31213223221 is a prime.

It is a super-2 number, since 2×31213223221² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31213223192 and 31213223201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213223231) 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, 340546 + ... + 422371.

It is an arithmetic number, because the mean of its divisors is an integer number (3941234388).

Almost surely, 2^31213223221 is an apocalyptic number.

It is an amenable number.

31213223221 is a deficient number, since it is larger than the sum of its proper divisors (316651883).

31213223221 is a wasteful number, since it uses less digits than its factorization.

31213223221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763331.

The product of its digits is 864, while the sum is 22.

Adding to 31213223221 its reverse (12232231213), we get a palindrome (43445454434).

The spelling of 31213223221 in words is "thirty-one billion, two hundred thirteen million, two hundred twenty-three thousand, two hundred twenty-one".