31331200221 has 10 divisors (see below), whose sum is σ = 46803397982. Its totient is φ = 20887466760.

The previous prime is 31331200193. The next prime is 31331200261. The reversal of 31331200221 is 12200213313.

It can be written as a sum of positive squares in only one way, i.e., 29999972025 + 1331228196 = 173205^2 + 36486^2 .

It is not a de Polignac number, because 31331200221 - 2⁶ = 31331200157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31331200194 and 31331200203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31331200261) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 193402390 + ... + 193402551.

Almost surely, 2^31331200221 is an apocalyptic number.

It is an amenable number.

31331200221 is a deficient number, since it is larger than the sum of its proper divisors (15472197761).

31331200221 is an equidigital number, since it uses as much as digits as its factorization.

31331200221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386804953 (or 386804944 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 31331200221 its reverse (12200213313), we get a palindrome (43531413534).

The spelling of 31331200221 in words is "thirty-one billion, three hundred thirty-one million, two hundred thousand, two hundred twenty-one".