31012111221 has 48 divisors (see below), whose sum is σ = 51880929408. Its totient is φ = 16332624000.

The previous prime is 31012111199. The next prime is 31012111231. The reversal of 31012111221 is 12211121013.

It is not a de Polignac number, because 31012111221 - 2²⁹ = 30475240309 is a prime.

It is a super-2 number, since 2×31012111221² (a number of 22 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 31012111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31012111231) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1250896 + ... + 1275446.

It is an arithmetic number, because the mean of its divisors is an integer number (1080852696).

Almost surely, 2^31012111221 is an apocalyptic number.

It is an amenable number.

31012111221 is a deficient number, since it is larger than the sum of its proper divisors (20868818187).

31012111221 is a wasteful number, since it uses less digits than its factorization.

31012111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25242 (or 25235 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 31012111221 its reverse (12211121013), we get a palindrome (43223232234).

The spelling of 31012111221 in words is "thirty-one billion, twelve million, one hundred eleven thousand, two hundred twenty-one".