20201221992 has 256 divisors, whose sum is σ = 62460426240. Its totient is φ = 5313724416.

The previous prime is 20201221981. The next prime is 20201221993. The reversal of 20201221992 is 29912210202.

It is not an unprimeable number, because it can be changed into a prime (20201221993) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 36930663 + ... + 36931209.

It is an arithmetic number, because the mean of its divisors is an integer number (243986040).

Almost surely, 2^20201221992 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20201221992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31230213120).

20201221992 is an abundant number, since it is smaller than the sum of its proper divisors (42259204248).

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

20201221992 is a wasteful number, since it uses less digits than its factorization.

20201221992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840 (or 836 counting only the distinct ones).

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

The spelling of 20201221992 in words is "twenty billion, two hundred one million, two hundred twenty-one thousand, nine hundred ninety-two".