21002112500 has 144 divisors (see below), whose sum is σ = 48065923584. Its totient is φ = 8019600000.

The previous prime is 21002112499. The next prime is 21002112541. The reversal of 21002112500 is 521120012.

It is a super-3 number, since 3×21002112500³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 32162174 + ... + 32162826.

It is an arithmetic number, because the mean of its divisors is an integer number (333791136).

Almost surely, 2^21002112500 is an apocalyptic number.

21002112500 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 21002112500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24032961792).

21002112500 is an abundant number, since it is smaller than the sum of its proper divisors (27063811084).

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

21002112500 is an equidigital number, since it uses as much as digits as its factorization.

21002112500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 796 (or 774 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

Adding to 21002112500 its reverse (521120012), we get a palindrome (21523232512).

The spelling of 21002112500 in words is "twenty-one billion, two million, one hundred twelve thousand, five hundred".