31231331103221 has 4 divisors (see below), whose sum is σ = 31231343582700. Its totient is φ = 31231318623744.

The previous prime is 31231331103211. The next prime is 31231331103241. The reversal of 31231331103221 is 12230113313213.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 29713248372196 + 1518082731025 = 5450986^2 + 1232105^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31231331103221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31231331103211) 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, 1043276 + ... + 7971893.

It is an arithmetic number, because the mean of its divisors is an integer number (7807835895675).

Almost surely, 2^{31231331103221} is an apocalyptic number.

It is an amenable number.

31231331103221 is a deficient number, since it is larger than the sum of its proper divisors (12479479).

31231331103221 is an equidigital number, since it uses as much as digits as its factorization.

31231331103221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12479478.

The product of its (nonzero) digits is 1944, while the sum is 26.

Adding to 31231331103221 its reverse (12230113313213), we get a palindrome (43461444416434).

The spelling of 31231331103221 in words is "thirty-one trillion, two hundred thirty-one billion, three hundred thirty-one million, one hundred three thousand, two hundred twenty-one".