21155321200 has 60 divisors (see below), whose sum is σ = 54735338728. Its totient is φ = 7811193600.

The previous prime is 21155321191. The next prime is 21155321219. The reversal of 21155321200 is 212355112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2028966 + ... + 2039365.

Almost surely, 2^21155321200 is an apocalyptic number.

21155321200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155321200 is an abundant number, since it is smaller than the sum of its proper divisors (33580017528).

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

21155321200 is a wasteful number, since it uses less digits than its factorization.

21155321200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4068362 (or 4068351 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

Adding to 21155321200 its reverse (212355112), we get a palindrome (21367676312).

The spelling of 21155321200 in words is "twenty-one billion, one hundred fifty-five million, three hundred twenty-one thousand, two hundred".