20012121220 has 96 divisors (see below), whose sum is σ = 51755026176. Its totient is φ = 6329664000.

The previous prime is 20012121209. The next prime is 20012121223. The reversal of 20012121220 is 2212121002.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 20012121220.

It is not an unprimeable number, because it can be changed into a prime (20012121223) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5405370 + ... + 5409070.

It is an arithmetic number, because the mean of its divisors is an integer number (539114856).

Almost surely, 2^20012121220 is an apocalyptic number.

20012121220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20012121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25877513088).

20012121220 is an abundant number, since it is smaller than the sum of its proper divisors (31742904956).

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

20012121220 is a wasteful number, since it uses less digits than its factorization.

20012121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6701 (or 6699 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 20012121220 its reverse (2212121002), we get a palindrome (22224242222).

The spelling of 20012121220 in words is "twenty billion, twelve million, one hundred twenty-one thousand, two hundred twenty".