20021231213 has 4 divisors (see below), whose sum is σ = 20023454748. Its totient is φ = 20019007680.

The previous prime is 20021231203. The next prime is 20021231231. The reversal of 20021231213 is 31213212002.

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 12813560809 + 7207670404 = 113197^2 + 84898^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021231213 - 2¹⁰ = 20021230189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021231191 and 20021231200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021231203) 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, 1098206 + ... + 1116287.

It is an arithmetic number, because the mean of its divisors is an integer number (5005863687).

Almost surely, 2^20021231213 is an apocalyptic number.

It is an amenable number.

20021231213 is a deficient number, since it is larger than the sum of its proper divisors (2223535).

20021231213 is an equidigital number, since it uses as much as digits as its factorization.

20021231213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2223534.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 20021231213 its reverse (31213212002), we get a palindrome (51234443215).

The spelling of 20021231213 in words is "twenty billion, twenty-one million, two hundred thirty-one thousand, two hundred thirteen".