21002055600 has 240 divisors, whose sum is σ = 69526335744. Its totient is φ = 5416320000.

The previous prime is 21002055563. The next prime is 21002055601. The reversal of 21002055600 is 655020012.

It is a tau number, because it is divible by the number of its divisors (240).

It is not an unprimeable number, because it can be changed into a prime (21002055601) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4513275 + ... + 4517925.

Almost surely, 2^21002055600 is an apocalyptic number.

21002055600 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 21002055600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34763167872).

21002055600 is an abundant number, since it is smaller than the sum of its proper divisors (48524280144).

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

21002055600 is a wasteful number, since it uses less digits than its factorization.

21002055600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4796 (or 4785 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

Adding to 21002055600 its reverse (655020012), we get a palindrome (21657075612).

The spelling of 21002055600 in words is "twenty-one billion, two million, fifty-five thousand, six hundred".