31103131221 has 16 divisors (see below), whose sum is σ = 46093801600. Its totient is φ = 20728630944.

The previous prime is 31103131121. The next prime is 31103131247. The reversal of 31103131221 is 12213130113.

31103131221 is a `hidden beast` number, since 311 + 0 + 3 + 131 + 221 = 666.

It is not a de Polignac number, because 31103131221 - 2²⁵ = 31069576789 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31103131194 and 31103131203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31103131291) 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, 103936 + ... + 270201.

It is an arithmetic number, because the mean of its divisors is an integer number (2880862600).

Almost surely, 2^31103131221 is an apocalyptic number.

It is an amenable number.

31103131221 is a deficient number, since it is larger than the sum of its proper divisors (14990670379).

31103131221 is a wasteful number, since it uses less digits than its factorization.

31103131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377225 (or 377219 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 31103131221 its reverse (12213130113), we get a palindrome (43316261334).

The spelling of 31103131221 in words is "thirty-one billion, one hundred three million, one hundred thirty-one thousand, two hundred twenty-one".