21105555200 has 54 divisors (see below), whose sum is σ = 52239562704. Its totient is φ = 8442219520.

The previous prime is 21105555187. The next prime is 21105555203. The reversal of 21105555200 is 255550112.

It is a self number, because there is not a number n which added to its sum of digits gives 21105555200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105555203) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1642472 + ... + 1655271.

Almost surely, 2^21105555200 is an apocalyptic number.

21105555200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21105555200 is an abundant number, since it is smaller than the sum of its proper divisors (31134007504).

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

21105555200 is an equidigital number, since it uses as much as digits as its factorization.

21105555200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3297769 (or 3297750 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 26.

The spelling of 21105555200 in words is "twenty-one billion, one hundred five million, five hundred fifty-five thousand, two hundred".