21604034880 has 560 divisors, whose sum is σ = 81554513040. Its totient is φ = 5419008000.

The previous prime is 21604034831. The next prime is 21604034887. The reversal of 21604034880 is 8843040612.

21604034880 is a `hidden beast` number, since 2 + 1 + 604 + 0 + 3 + 48 + 8 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 409333824 + 21194701056 = 20232^2 + 145584^2 .

It is a super-2 number, since 2×21604034880² (a number of 21 digits) contains 22 as substring.

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 (21604034887) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 30818530 + ... + 30819230.

It is an arithmetic number, because the mean of its divisors is an integer number (145633059).

Almost surely, 2^21604034880 is an apocalyptic number.

21604034880 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 21604034880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40777256520).

21604034880 is an abundant number, since it is smaller than the sum of its proper divisors (59950478160).

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

21604034880 is a wasteful number, since it uses less digits than its factorization.

21604034880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800 (or 781 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The spelling of 21604034880 in words is "twenty-one billion, six hundred four million, thirty-four thousand, eight hundred eighty".