21042235500 has 384 divisors, whose sum is σ = 72454846464. Its totient is φ = 4678272000.

The previous prime is 21042235499. The next prime is 21042235507. The reversal of 21042235500 is 553224012.

It is not an unprimeable number, because it can be changed into a prime (21042235507) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 56413314 + ... + 56413686.

It is an arithmetic number, because the mean of its divisors is an integer number (188684496).

Almost surely, 2^21042235500 is an apocalyptic number.

21042235500 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 21042235500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36227423232).

21042235500 is an abundant number, since it is smaller than the sum of its proper divisors (51412610964).

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

21042235500 is a wasteful number, since it uses less digits than its factorization.

21042235500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

Adding to 21042235500 its reverse (553224012), we get a palindrome (21595459512).

The spelling of 21042235500 in words is "twenty-one billion, forty-two million, two hundred thirty-five thousand, five hundred".