312021111221 has 4 divisors (see below), whose sum is σ = 330375294252. Its totient is φ = 293666928192.

The previous prime is 312021111217. The next prime is 312021111223. The reversal of 312021111221 is 122111120213.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 228829246321 + 83191864900 = 478361^2 + 288430^2 .

It is a cyclic number.

It is not a de Polignac number, because 312021111221 - 2² = 312021111217 is a prime.

It is a super-2 number, since 2×312021111221² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 18354183013 = 312021111221 / (3 + 1 + 2 + 0 + 2 + 1 + 1 + 1 + 1 + 2 + 2 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 312021111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (312021111223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9177091490 + ... + 9177091523.

It is an arithmetic number, because the mean of its divisors is an integer number (82593823563).

Almost surely, 2^312021111221 is an apocalyptic number.

It is an amenable number.

312021111221 is a deficient number, since it is larger than the sum of its proper divisors (18354183031).

312021111221 is a wasteful number, since it uses less digits than its factorization.

312021111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18354183030.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 312021111221 its reverse (122111120213), we get a palindrome (434132231434).

The spelling of 312021111221 in words is "three hundred twelve billion, twenty-one million, one hundred eleven thousand, two hundred twenty-one".