21221330100 has 72 divisors (see below), whose sum is σ = 61622285088. Its totient is φ = 5638569600.

The previous prime is 21221330089. The next prime is 21221330113. The reversal of 21221330100 is 103312212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21221330100.

It is a congruent number.

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, 44586 + ... + 210785.

Almost surely, 2^21221330100 is an apocalyptic number.

21221330100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221330100 is an abundant number, since it is smaller than the sum of its proper divisors (40400954988).

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

21221330100 is a wasteful number, since it uses less digits than its factorization.

21221330100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255665 (or 255658 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21221330100 its reverse (103312212), we get a palindrome (21324642312).

The spelling of 21221330100 in words is "twenty-one billion, two hundred twenty-one million, three hundred thirty thousand, one hundred".