31031212221 has 6 divisors (see below), whose sum is σ = 44822862110. Its totient is φ = 20687474808.

The previous prime is 31031212213. The next prime is 31031212231. The reversal of 31031212221 is 12221213013.

31031212221 is a `hidden beast` number, since 310 + 312 + 1 + 22 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 30971072196 + 60140025 = 175986^2 + 7755^2 .

It is not a de Polignac number, because 31031212221 - 2³ = 31031212213 is a prime.

It is a super-2 number, since 2×31031212221² (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 = 31031212194 and 31031212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31031212231) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1723956226 + ... + 1723956243.

Almost surely, 2^31031212221 is an apocalyptic number.

It is an amenable number.

31031212221 is a deficient number, since it is larger than the sum of its proper divisors (13791649889).

31031212221 is a wasteful number, since it uses less digits than its factorization.

31031212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3447912475 (or 3447912472 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 31031212221 its reverse (12221213013), we get a palindrome (43252425234).

The spelling of 31031212221 in words is "thirty-one billion, thirty-one million, two hundred twelve thousand, two hundred twenty-one".