21220131213 has 6 divisors (see below), whose sum is σ = 30651300654. Its totient is φ = 14146754136.

The previous prime is 21220131211. The next prime is 21220131239. The reversal of 21220131213 is 31213102212.

It can be written as a sum of positive squares in only one way, i.e., 12592879524 + 8627251689 = 112218^2 + 92883^2 .

It is not a de Polignac number, because 21220131213 - 2¹ = 21220131211 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220131211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1178896170 + ... + 1178896187.

It is an arithmetic number, because the mean of its divisors is an integer number (5108550109).

Almost surely, 2^21220131213 is an apocalyptic number.

It is an amenable number.

21220131213 is a deficient number, since it is larger than the sum of its proper divisors (9431169441).

21220131213 is a wasteful number, since it uses less digits than its factorization.

21220131213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2357792363 (or 2357792360 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21220131213 its reverse (31213102212), we get a palindrome (52433233425).

The spelling of 21220131213 in words is "twenty-one billion, two hundred twenty million, one hundred thirty-one thousand, two hundred thirteen".