21001303220 has 48 divisors (see below), whose sum is σ = 46112976000. Its totient is φ = 8019090816.

The previous prime is 21001303189. The next prime is 21001303223. The reversal of 21001303220 is 2230310012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21001303195 and 21001303204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001303223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 183794 + ... + 275286.

It is an arithmetic number, because the mean of its divisors is an integer number (960687000).

Almost surely, 2^21001303220 is an apocalyptic number.

21001303220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21001303220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23056488000).

21001303220 is an abundant number, since it is smaller than the sum of its proper divisors (25111672780).

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

21001303220 is a wasteful number, since it uses less digits than its factorization.

21001303220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92024 (or 92022 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

Adding to 21001303220 its reverse (2230310012), we get a palindrome (23231613232).

The spelling of 21001303220 in words is "twenty-one billion, one million, three hundred three thousand, two hundred twenty".