21187980000 has 1200 divisors, whose sum is σ = 90017872560. Its totient is φ = 4838400000.

The previous prime is 21187979993. The next prime is 21187980001. The reversal of 21187980000 is 8978112.

It is a tau number, because it is divible by the number of its divisors (1200).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21187980001) by changing a digit.

It is a polite number, since it can be written in 199 ways as a sum of consecutive naturals, for example, 516779980 + ... + 516780020.

Almost surely, 2^21187980000 is an apocalyptic number.

21187980000 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 21187980000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45008936280).

21187980000 is an abundant number, since it is smaller than the sum of its proper divisors (68829892560).

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

21187980000 is a wasteful number, since it uses less digits than its factorization.

21187980000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The spelling of 21187980000 in words is "twenty-one billion, one hundred eighty-seven million, nine hundred eighty thousand".