20021313221 has 18 divisors (see below), whose sum is σ = 25219466802. Its totient is φ = 15841032480.

The previous prime is 20021313209. The next prime is 20021313269. The reversal of 20021313221 is 12231312002.

It can be written as a sum of positive squares in 3 ways, for example, as 470282596 + 19551030625 = 21686^2 + 139825^2 .

It is not a de Polignac number, because 20021313221 - 2⁶ = 20021313157 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20021313221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021312221) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1200590 + ... + 1217151.

It is an arithmetic number, because the mean of its divisors is an integer number (1401081489).

Almost surely, 2^20021313221 is an apocalyptic number.

It is an amenable number.

20021313221 is a deficient number, since it is larger than the sum of its proper divisors (5198153581).

20021313221 is a wasteful number, since it uses less digits than its factorization.

20021313221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2417781 (or 2417761 counting only the distinct ones).

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

Adding to 20021313221 its reverse (12231312002), we get a palindrome (32252625223).

The spelling of 20021313221 in words is "twenty billion, twenty-one million, three hundred thirteen thousand, two hundred twenty-one".