21211020220 has 48 divisors (see below), whose sum is σ = 49085134560. Its totient is φ = 7649623296.

The previous prime is 21211020191. The next prime is 21211020269. The reversal of 21211020220 is 2202011212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 21211020220.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 937435 + ... + 959794.

It is an arithmetic number, because the mean of its divisors is an integer number (1022606970).

Almost surely, 2^21211020220 is an apocalyptic number.

21211020220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211020220 is an abundant number, since it is smaller than the sum of its proper divisors (27874114340).

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

21211020220 is a wasteful number, since it uses less digits than its factorization.

21211020220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1897294 (or 1897292 counting only the distinct ones).

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

Adding to 21211020220 its reverse (2202011212), we get a palindrome (23413031432).

The spelling of 21211020220 in words is "twenty-one billion, two hundred eleven million, twenty thousand, two hundred twenty".