31211300221 has 4 divisors (see below), whose sum is σ = 31800192732. Its totient is φ = 30622407712.

The previous prime is 31211300203. The next prime is 31211300227. The reversal of 31211300221 is 12200311213.

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 28220304121 + 2990996100 = 167989^2 + 54690^2 .

It is a cyclic number.

It is not a de Polignac number, because 31211300221 - 2⁵ = 31211300189 is a prime.

It is a super-2 number, since 2×31211300221² (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 = 31211300195 and 31211300204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31211300227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 294446176 + ... + 294446281.

It is an arithmetic number, because the mean of its divisors is an integer number (7950048183).

Almost surely, 2^31211300221 is an apocalyptic number.

It is an amenable number.

31211300221 is a deficient number, since it is larger than the sum of its proper divisors (588892511).

31211300221 is an equidigital number, since it uses as much as digits as its factorization.

31211300221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 588892510.

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

Adding to 31211300221 its reverse (12200311213), we get a palindrome (43411611434).

The spelling of 31211300221 in words is "thirty-one billion, two hundred eleven million, three hundred thousand, two hundred twenty-one".