31122221111 has 4 divisors (see below), whose sum is σ = 31124089224. Its totient is φ = 31120353000.

The previous prime is 31122221071. The next prime is 31122221183. The reversal of 31122221111 is 11112222113.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11112222113 = 131 ⋅84826123.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31122221111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31122221111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31122220111) 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, 908840 + ... + 942461.

It is an arithmetic number, because the mean of its divisors is an integer number (7781022306).

Almost surely, 2^31122221111 is an apocalyptic number.

31122221111 is a deficient number, since it is larger than the sum of its proper divisors (1868113).

31122221111 is a wasteful number, since it uses less digits than its factorization.

31122221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1868112.

The product of its digits is 48, while the sum is 17.

Adding to 31122221111 its reverse (11112222113), we get a palindrome (42234443224).

The spelling of 31122221111 in words is "thirty-one billion, one hundred twenty-two million, two hundred twenty-one thousand, one hundred eleven".