31220111221 has 8 divisors (see below), whose sum is σ = 33627587000. Its totient is φ = 28813482432.

The previous prime is 31220111213. The next prime is 31220111281. The reversal of 31220111221 is 12211102213.

It can be written as a sum of positive squares in 4 ways, for example, as 240591121 + 30979520100 = 15511^2 + 176010^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31220111221 - 2³ = 31220111213 is a prime.

It is a super-2 number, since 2×31220111221² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31220111195 and 31220111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31220111281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 134130 + ... + 283603.

It is an arithmetic number, because the mean of its divisors is an integer number (4203448375).

Almost surely, 2^31220111221 is an apocalyptic number.

It is an amenable number.

31220111221 is a deficient number, since it is larger than the sum of its proper divisors (2407475779).

31220111221 is a wasteful number, since it uses less digits than its factorization.

31220111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423495.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 31220111221 its reverse (12211102213), we get a palindrome (43431213434).

The spelling of 31220111221 in words is "thirty-one billion, two hundred twenty million, one hundred eleven thousand, two hundred twenty-one".