21001120220 has 24 divisors (see below), whose sum is σ = 44110173408. Its totient is φ = 8398958400.

The previous prime is 21001120193. The next prime is 21001120243. The reversal of 21001120220 is 2202110012.

It is a happy number.

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 7 ways as a sum of consecutive naturals, for example, 26225 + ... + 206615.

It is an arithmetic number, because the mean of its divisors is an integer number (1837923892).

Almost surely, 2^21001120220 is an apocalyptic number.

21001120220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001120220 is an abundant number, since it is smaller than the sum of its proper divisors (23109053188).

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

21001120220 is a wasteful number, since it uses less digits than its factorization.

21001120220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186221 (or 186219 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21001120220 its reverse (2202110012), we get a palindrome (23203230232).

The spelling of 21001120220 in words is "twenty-one billion, one million, one hundred twenty thousand, two hundred twenty".