21180240000 has 480 divisors, whose sum is σ = 79534540800. Its totient is φ = 5398272000.

The previous prime is 21180239981. The next prime is 21180240071. The reversal of 21180240000 is 4208112.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 16559361 + ... + 16560639.

It is an arithmetic number, because the mean of its divisors is an integer number (165696960).

Almost surely, 2^21180240000 is an apocalyptic number.

21180240000 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 21180240000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39767270400).

21180240000 is an abundant number, since it is smaller than the sum of its proper divisors (58354300800).

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

21180240000 is a wasteful number, since it uses less digits than its factorization.

21180240000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342 (or 1312 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21180240000 its reverse (4208112), we get a palindrome (21184448112).

The spelling of 21180240000 in words is "twenty-one billion, one hundred eighty million, two hundred forty thousand".