31123312211 has 4 divisors (see below), whose sum is σ = 31160947032. Its totient is φ = 31085677392.

The previous prime is 31123312117. The next prime is 31123312261. The reversal of 31123312211 is 11221332113.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31123312211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31123312261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18816170 + ... + 18817823.

It is an arithmetic number, because the mean of its divisors is an integer number (7790236758).

Almost surely, 2^31123312211 is an apocalyptic number.

31123312211 is a deficient number, since it is larger than the sum of its proper divisors (37634821).

31123312211 is an equidigital number, since it uses as much as digits as its factorization.

31123312211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37634820.

The product of its digits is 216, while the sum is 20.

Adding to 31123312211 its reverse (11221332113), we get a palindrome (42344644324).

The spelling of 31123312211 in words is "thirty-one billion, one hundred twenty-three million, three hundred twelve thousand, two hundred eleven".