21002120220 has 48 divisors (see below), whose sum is σ = 59052026880.
Its totient is φ = 5577128256.
The previous prime is 21002120213. The next prime is 21002120257. The reversal of 21002120220 is 2202120012.
Adding to 21002120220 its reverse (2202120012), we get a palindrome (23204240232).
It is a Harshad number since it is a multiple of its sum of digits (12).
It is a junction number, because it is equal to n+sod(n) for n = 21002120196 and 21002120205.
It is a congruent number.
It is an unprimeable number.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 717952 + ... + 746631.
It is an arithmetic number, because the mean of its divisors is an integer number (1230250560).
Almost surely, 221002120220 is an apocalyptic number.
21002120220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
21002120220 is an abundant number, since it is smaller than the sum of its proper divisors (38049906660).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21002120220 is a wasteful number, since it uses less digits than its factorization.
21002120220 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1464834 (or 1464832 counting only the distinct ones).
The product of its (nonzero) digits is 32, while the sum is 12.
The spelling of 21002120220 in words is "twenty-one billion, two million, one hundred twenty thousand, two hundred twenty".