20021221992 has 32 divisors (see below), whose sum is σ = 50091429600. Its totient is φ = 6668624064.

The previous prime is 20021221991. The next prime is 20021222017. The reversal of 20021221992 is 29912212002.

It is not an unprimeable number, because it can be changed into a prime (20021221991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 287767 + ... + 350502.

It is an arithmetic number, because the mean of its divisors is an integer number (1565357175).

Almost surely, 2^20021221992 is an apocalyptic number.

It is an amenable number.

20021221992 is an abundant number, since it is smaller than the sum of its proper divisors (30070207608).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20021221992 is a wasteful number, since it uses less digits than its factorization.

20021221992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639585 (or 639581 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

Adding to 20021221992 its reverse (29912212002), we get a palindrome (49933433994).

The spelling of 20021221992 in words is "twenty billion, twenty-one million, two hundred twenty-one thousand, nine hundred ninety-two".