21101203220 has 12 divisors (see below), whose sum is σ = 44312526804. Its totient is φ = 8440481280.

The previous prime is 21101203181. The next prime is 21101203223. The reversal of 21101203220 is 2230210112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 8779315204 + 12321888016 = 93698^2 + 111004^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21101203195 and 21101203204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101203223) 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, 527530061 + ... + 527530100.

It is an arithmetic number, because the mean of its divisors is an integer number (3692710567).

Almost surely, 2^21101203220 is an apocalyptic number.

21101203220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101203220 is an abundant number, since it is smaller than the sum of its proper divisors (23211323584).

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

21101203220 is a wasteful number, since it uses less digits than its factorization.

21101203220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1055060170 (or 1055060168 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21101203220 its reverse (2230210112), we get a palindrome (23331413332).

The spelling of 21101203220 in words is "twenty-one billion, one hundred one million, two hundred three thousand, two hundred twenty".