312121111221 has 12 divisors (see below), whose sum is σ = 451105431660. Its totient is φ = 207958974720.

The previous prime is 312121111207. The next prime is 312121111259. The reversal of 312121111221 is 122111121213.

It is a happy number.

312121111221 is a `hidden beast` number, since 312 + 1 + 21 + 111 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 204701048721 + 107420062500 = 452439^2 + 327750^2 .

It is not a de Polignac number, because 312121111221 - 2¹⁴ = 312121094837 is a prime.

It is a super-2 number, since 2×312121111221² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 312121111194 and 312121111203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (312121111121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10130940 + ... + 10161701.

It is an arithmetic number, because the mean of its divisors is an integer number (37592119305).

Almost surely, 2^312121111221 is an apocalyptic number.

It is an amenable number.

312121111221 is a deficient number, since it is larger than the sum of its proper divisors (138984320439).

312121111221 is a wasteful number, since it uses less digits than its factorization.

312121111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20294356 (or 20294353 counting only the distinct ones).

The product of its digits is 48, while the sum is 18.

Adding to 312121111221 its reverse (122111121213), we get a palindrome (434232232434).

The spelling of 312121111221 in words is "three hundred twelve billion, one hundred twenty-one million, one hundred eleven thousand, two hundred twenty-one".