21001010220 has 72 divisors (see below), whose sum is σ = 64359850464. Its totient is φ = 5542530048.

The previous prime is 21001010179. The next prime is 21001010237. The reversal of 21001010220 is 2201010012.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 583944 + ... + 618863.

It is an arithmetic number, because the mean of its divisors is an integer number (893886812).

Almost surely, 2^21001010220 is an apocalyptic number.

21001010220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001010220 is an abundant number, since it is smaller than the sum of its proper divisors (43358840244).

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

21001010220 is a wasteful number, since it uses less digits than its factorization.

21001010220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1202919 (or 1202914 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21001010220 its reverse (2201010012), we get a palindrome (23202020232).

The spelling of 21001010220 in words is "twenty-one billion, one million, ten thousand, two hundred twenty".