31310120221 has 4 divisors (see below), whose sum is σ = 31474047744. Its totient is φ = 31146192700.

The previous prime is 31310120213. The next prime is 31310120227. The reversal of 31310120221 is 12202101313.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12202101313 = 107761 ⋅113233.

It is a cyclic number.

It is not a de Polignac number, because 31310120221 - 2³ = 31310120213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31310120195 and 31310120204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31310120227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81963475 + ... + 81963856.

It is an arithmetic number, because the mean of its divisors is an integer number (7868511936).

Almost surely, 2^31310120221 is an apocalyptic number.

It is an amenable number.

31310120221 is a deficient number, since it is larger than the sum of its proper divisors (163927523).

31310120221 is a wasteful number, since it uses less digits than its factorization.

31310120221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163927522.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 31310120221 its reverse (12202101313), we get a palindrome (43512221534).

The spelling of 31310120221 in words is "thirty-one billion, three hundred ten million, one hundred twenty thousand, two hundred twenty-one".