21805002871764 has 48 divisors (see below), whose sum is σ = 58202105136000. Its totient is φ = 6224061805056.

The previous prime is 21805002871747. The next prime is 21805002871781. The reversal of 21805002871764 is 46717820050812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21805002871747) and next prime (21805002871781).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 123640849 + ... + 123817080.

It is an arithmetic number, because the mean of its divisors is an integer number (1212543857000).

Almost surely, 2^{21805002871764} is an apocalyptic number.

It is an amenable number.

21805002871764 is an abundant number, since it is smaller than the sum of its proper divisors (36397102264236).

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

21805002871764 is a wasteful number, since it uses less digits than its factorization.

21805002871764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247458992 (or 247458990 counting only the distinct ones).

The product of its (nonzero) digits is 1505280, while the sum is 51.

The spelling of 21805002871764 in words is "twenty-one trillion, eight hundred five billion, two million, eight hundred seventy-one thousand, seven hundred sixty-four".