221010100020 has 48 divisors (see below), whose sum is σ = 687586979520. Its totient is φ = 58936026528.

The previous prime is 221010100007. The next prime is 221010100021. The reversal of 221010100020 is 20001010122.

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

It is a junction number, because it is equal to n+sod(n) for n = 221010099975 and 221010100011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221010100021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 204638442 + ... + 204639521.

It is an arithmetic number, because the mean of its divisors is an integer number (14324728740).

Almost surely, 2^221010100020 is an apocalyptic number.

221010100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221010100020 is an abundant number, since it is smaller than the sum of its proper divisors (466576879500).

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

221010100020 is a wasteful number, since it uses less digits than its factorization.

221010100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409277981 (or 409277973 counting only the distinct ones).

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

Adding to 221010100020 its reverse (20001010122), we get a palindrome (241011110142).

The spelling of 221010100020 in words is "two hundred twenty-one billion, ten million, one hundred thousand, twenty".