31213313301221 has 4 divisors (see below), whose sum is σ = 33049390554252. Its totient is φ = 29377236048192.

The previous prime is 31213313301133. The next prime is 31213313301259. The reversal of 31213313301221 is 12210331331213.

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 28152458080321 + 3060855220900 = 5305889^2 + 1749530^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31213313301221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213313301281) 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, 918038626490 + ... + 918038626523.

It is an arithmetic number, because the mean of its divisors is an integer number (8262347638563).

Almost surely, 2^{31213313301221} is an apocalyptic number.

It is an amenable number.

31213313301221 is a deficient number, since it is larger than the sum of its proper divisors (1836077253031).

31213313301221 is a wasteful number, since it uses less digits than its factorization.

31213313301221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1836077253030.

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

Adding to 31213313301221 its reverse (12210331331213), we get a palindrome (43423644632434).

The spelling of 31213313301221 in words is "thirty-one trillion, two hundred thirteen billion, three hundred thirteen million, three hundred one thousand, two hundred twenty-one".