21031022100 has 216 divisors, whose sum is σ = 70406986720. Its totient is φ = 4829932800.

The previous prime is 21031022093. The next prime is 21031022153. The reversal of 21031022100 is 122013012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 674454 + ... + 704946.

Almost surely, 2^21031022100 is an apocalyptic number.

21031022100 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 21031022100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35203493360).

21031022100 is an abundant number, since it is smaller than the sum of its proper divisors (49375964620).

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

21031022100 is a wasteful number, since it uses less digits than its factorization.

21031022100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30551 (or 30533 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21031022100 its reverse (122013012), we get a palindrome (21153035112).

The spelling of 21031022100 in words is "twenty-one billion, thirty-one million, twenty-two thousand, one hundred".