20212121020 has 96 divisors (see below), whose sum is σ = 52376688000. Its totient is φ = 6380135424.

The previous prime is 20212121009. The next prime is 20212121021. The reversal of 20212121020 is 2012121202.

It is a happy number.

It is a super-2 number, since 2×20212121020² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20212121021) 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, 693706 + ... + 722254.

It is an arithmetic number, because the mean of its divisors is an integer number (545590500).

Almost surely, 2^20212121020 is an apocalyptic number.

20212121020 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 20212121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26188344000).

20212121020 is an abundant number, since it is smaller than the sum of its proper divisors (32164566980).

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

20212121020 is a wasteful number, since it uses less digits than its factorization.

20212121020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28967 (or 28965 counting only the distinct ones).

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

Adding to 20212121020 its reverse (2012121202), we get a palindrome (22224242222).

The spelling of 20212121020 in words is "twenty billion, two hundred twelve million, one hundred twenty-one thousand, twenty".