21020002121220 has 24 divisors (see below), whose sum is σ = 58856005939584. Its totient is φ = 5605333898976.

The previous prime is 21020002121213. The next prime is 21020002121227. The reversal of 21020002121220 is 2212120002012.

It is an interprime number because it is at equal distance from previous prime (21020002121213) and next prime (21020002121227).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21020002121220.

It is not an unprimeable number, because it can be changed into a prime (21020002121227) 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, 175166684284 + ... + 175166684403.

It is an arithmetic number, because the mean of its divisors is an integer number (2452333580816).

Almost surely, 2^{21020002121220} is an apocalyptic number.

21020002121220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020002121220 is an abundant number, since it is smaller than the sum of its proper divisors (37836003818364).

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

21020002121220 is a wasteful number, since it uses less digits than its factorization.

21020002121220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350333368699 (or 350333368697 counting only the distinct ones).

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

Adding to 21020002121220 its reverse (2212120002012), we get a palindrome (23232122123232).

The spelling of 21020002121220 in words is "twenty-one trillion, twenty billion, two million, one hundred twenty-one thousand, two hundred twenty".