21604242240 has 1120 divisors, whose sum is σ = 95170166784. Its totient is φ = 4543672320.

The previous prime is 21604242199. The next prime is 21604242251. The reversal of 21604242240 is 4224240612.

21604242240 is a `hidden beast` number, since 2 + 16 + 0 + 424 + 224 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1120).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 129366637 + ... + 129366803.

Almost surely, 2^21604242240 is an apocalyptic number.

21604242240 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 21604242240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47585083392).

21604242240 is an abundant number, since it is smaller than the sum of its proper divisors (73565924544).

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

21604242240 is a wasteful number, since it uses less digits than its factorization.

21604242240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257 (or 238 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 27.

Adding to 21604242240 its reverse (4224240612), we get a palindrome (25828482852).

The spelling of 21604242240 in words is "twenty-one billion, six hundred four million, two hundred forty-two thousand, two hundred forty".