21206617805484 has 540 divisors, whose sum is σ = 61867462706280. Its totient is φ = 6332041900800.

The previous prime is 21206617805449. The next prime is 21206617805561. The reversal of 21206617805484 is 48450871660212.

21206617805484 is a `hidden beast` number, since 2 + 1 + 2 + 0 + 6 + 6 + 17 + 80 + 548 + 4 = 666.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 21206617805484.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 5506780159 + ... + 5506784009.

It is an arithmetic number, because the mean of its divisors is an integer number (114569375382).

Almost surely, 2^{21206617805484} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21206617805484, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30933731353140).

21206617805484 is an abundant number, since it is smaller than the sum of its proper divisors (40660844900796).

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

21206617805484 is a wasteful number, since it uses less digits than its factorization.

21206617805484 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4040 (or 3987 counting only the distinct ones).

The product of its (nonzero) digits is 5160960, while the sum is 54.

The spelling of 21206617805484 in words is "twenty-one trillion, two hundred six billion, six hundred seventeen million, eight hundred five thousand, four hundred eighty-four".