21043031100 has 288 divisors, whose sum is σ = 75968471040. Its totient is φ = 4378613760.

The previous prime is 21043031099. The next prime is 21043031117. The reversal of 21043031100 is 113034012.

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 21043031100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1987621 + ... + 1998179.

Almost surely, 2^21043031100 is an apocalyptic number.

21043031100 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 21043031100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37984235520).

21043031100 is an abundant number, since it is smaller than the sum of its proper divisors (54925439940).

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

21043031100 is a wasteful number, since it uses less digits than its factorization.

21043031100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10669 (or 10662 counting only the distinct ones).

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

Adding to 21043031100 its reverse (113034012), we get a palindrome (21156065112).

The spelling of 21043031100 in words is "twenty-one billion, forty-three million, thirty-one thousand, one hundred".