31123221121 has 16 divisors (see below), whose sum is σ = 34452756864. Its totient is φ = 27965101824.

The previous prime is 31123221049. The next prime is 31123221137. The reversal of 31123221121 is 12112232113.

It is a cyclic number.

It is not a de Polignac number, because 31123221121 - 2¹¹ = 31123219073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31123225121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128395 + ... + 280591.

It is an arithmetic number, because the mean of its divisors is an integer number (2153297304).

Almost surely, 2^31123221121 is an apocalyptic number.

It is an amenable number.

31123221121 is a deficient number, since it is larger than the sum of its proper divisors (3329535743).

31123221121 is a wasteful number, since it uses less digits than its factorization.

31123221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152760.

The product of its digits is 144, while the sum is 19.

Adding to 31123221121 its reverse (12112232113), we get a palindrome (43235453234).

The spelling of 31123221121 in words is "thirty-one billion, one hundred twenty-three million, two hundred twenty-one thousand, one hundred twenty-one".