20021212221 has 8 divisors (see below), whose sum is σ = 27093381984. Its totient is φ = 13148258640.

The previous prime is 20021212207. The next prime is 20021212223. The reversal of 20021212221 is 12221212002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20021212221 - 2⁶ = 20021212157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20021212221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021212223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49803810 + ... + 49804211.

It is an arithmetic number, because the mean of its divisors is an integer number (3386672748).

Almost surely, 2^20021212221 is an apocalyptic number.

It is an amenable number.

20021212221 is a deficient number, since it is larger than the sum of its proper divisors (7072169763).

20021212221 is an equidigital number, since it uses as much as digits as its factorization.

20021212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99608091.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 20021212221 its reverse (12221212002), we get a palindrome (32242424223).

The spelling of 20021212221 in words is "twenty billion, twenty-one million, two hundred twelve thousand, two hundred twenty-one".