31112122221 has 16 divisors (see below), whose sum is σ = 46127030400. Its totient is φ = 20725665984.

The previous prime is 31112122213. The next prime is 31112122259. The reversal of 31112122221 is 12222121113.

31112122221 is a `hidden beast` number, since 311 + 12 + 122 + 221 = 666.

It is not a de Polignac number, because 31112122221 - 2³ = 31112122213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31112122194 and 31112122203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31112122621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 401196 + ... + 472421.

It is an arithmetic number, because the mean of its divisors is an integer number (2882939400).

Almost surely, 2^31112122221 is an apocalyptic number.

It is an amenable number.

31112122221 is a deficient number, since it is larger than the sum of its proper divisors (15014908179).

31112122221 is a wasteful number, since it uses less digits than its factorization.

31112122221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874945 (or 874939 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 31112122221 its reverse (12222121113), we get a palindrome (43334243334).

The spelling of 31112122221 in words is "thirty-one billion, one hundred twelve million, one hundred twenty-two thousand, two hundred twenty-one".