21204240000 has 320 divisors, whose sum is σ = 71753156640. Its totient is φ = 5544448000.

The previous prime is 21204239977. The next prime is 21204240011. The reversal of 21204240000 is 4240212.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 12719167 + ... + 12720833.

Almost surely, 2^21204240000 is an apocalyptic number.

21204240000 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 21204240000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35876578320).

21204240000 is an abundant number, since it is smaller than the sum of its proper divisors (50548916640).

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

21204240000 is an equidigital number, since it uses as much as digits as its factorization.

21204240000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1757 (or 1730 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

Adding to 21204240000 its reverse (4240212), we get a palindrome (21208480212).

The spelling of 21204240000 in words is "twenty-one billion, two hundred four million, two hundred forty thousand".