21102121200 has 120 divisors (see below), whose sum is σ = 69424223728. Its totient is φ = 5475133440.

The previous prime is 21102121153. The next prime is 21102121217. The reversal of 21102121200 is 212120112.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 193237 + ... + 282036.

Almost surely, 2^21102121200 is an apocalyptic number.

21102121200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21102121200 is an abundant number, since it is smaller than the sum of its proper divisors (48322102528).

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

21102121200 is a wasteful number, since it uses less digits than its factorization.

21102121200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475331 (or 475320 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21102121200 its reverse (212120112), we get a palindrome (21314241312).

It can be divided in two parts, 211021 and 21200, that added together give a triangular number (232221 = T₆₈₁).

The spelling of 21102121200 in words is "twenty-one billion, one hundred two million, one hundred twenty-one thousand, two hundred".