31123313221 has 64 divisors (see below), whose sum is σ = 42622304256. Its totient is φ = 21942835200.

The previous prime is 31123313219. The next prime is 31123313237. The reversal of 31123313221 is 12231332113.

It is not a de Polignac number, because 31123313221 - 2¹ = 31123313219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31123313192 and 31123313201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31123313021) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 14954901 + ... + 14956981.

It is an arithmetic number, because the mean of its divisors is an integer number (665973504).

Almost surely, 2^31123313221 is an apocalyptic number.

It is an amenable number.

31123313221 is a deficient number, since it is larger than the sum of its proper divisors (11498991035).

31123313221 is a wasteful number, since it uses less digits than its factorization.

31123313221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2402.

The product of its digits is 648, while the sum is 22.

Adding to 31123313221 its reverse (12231332113), we get a palindrome (43354645334).

The spelling of 31123313221 in words is "thirty-one billion, one hundred twenty-three million, three hundred thirteen thousand, two hundred twenty-one".