21647821086803 has 4 divisors (see below), whose sum is σ = 21690351187680. Its totient is φ = 21605290985928.

The previous prime is 21647821086769. The next prime is 21647821086917. The reversal of 21647821086803 is 30868012874612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21647821086803 - 2¹⁴ = 21647821070419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21647821086403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21265049675 + ... + 21265050692.

It is an arithmetic number, because the mean of its divisors is an integer number (5422587796920).

Almost surely, 2^{21647821086803} is an apocalyptic number.

21647821086803 is a deficient number, since it is larger than the sum of its proper divisors (42530100877).

21647821086803 is an equidigital number, since it uses as much as digits as its factorization.

21647821086803 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42530100876.

The product of its (nonzero) digits is 6193152, while the sum is 56.

The spelling of 21647821086803 in words is "twenty-one trillion, six hundred forty-seven billion, eight hundred twenty-one million, eighty-six thousand, eight hundred three".