21021102220 has 24 divisors (see below), whose sum is σ = 44197599600. Its totient is φ = 8398291392.

The previous prime is 21021102209. The next prime is 21021102283. The reversal of 21021102220 is 2220112012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021102220.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 617350 + ... + 650509.

It is an arithmetic number, because the mean of its divisors is an integer number (1841566650).

Almost surely, 2^21021102220 is an apocalyptic number.

21021102220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021102220 is an abundant number, since it is smaller than the sum of its proper divisors (23176497380).

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

21021102220 is a wasteful number, since it uses less digits than its factorization.

21021102220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1268697 (or 1268695 counting only the distinct ones).

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

Adding to 21021102220 its reverse (2220112012), we get a palindrome (23241214232).

The spelling of 21021102220 in words is "twenty-one billion, twenty-one million, one hundred two thousand, two hundred twenty".