21000120220 has 12 divisors (see below), whose sum is σ = 44100252504. Its totient is φ = 8400048080.

The previous prime is 21000120217. The next prime is 21000120221. The reversal of 21000120220 is 2202100012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21000120197 and 21000120206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000120221) 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 3 ways as a sum of consecutive naturals, for example, 525002986 + ... + 525003025.

It is an arithmetic number, because the mean of its divisors is an integer number (3675021042).

Almost surely, 2^21000120220 is an apocalyptic number.

21000120220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000120220 is an abundant number, since it is smaller than the sum of its proper divisors (23100132284).

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

21000120220 is a wasteful number, since it uses less digits than its factorization.

21000120220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050006020 (or 1050006018 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21000120220 its reverse (2202100012), we get a palindrome (23202220232).

The spelling of 21000120220 in words is "twenty-one billion, one hundred twenty thousand, two hundred twenty".