21280111807845 has 64 divisors (see below), whose sum is σ = 38924747956224. Its totient is φ = 9826680568320.

The previous prime is 21280111807813. The next prime is 21280111807919. The reversal of 21280111807845 is 54870811108212.

It is not a de Polignac number, because 21280111807845 - 2⁵ = 21280111807813 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21280111807794 and 21280111807803.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11148829 + ... + 12917298.

It is an arithmetic number, because the mean of its divisors is an integer number (608199186816).

Almost surely, 2^{21280111807845} is an apocalyptic number.

It is an amenable number.

21280111807845 is a deficient number, since it is larger than the sum of its proper divisors (17644636148379).

21280111807845 is a wasteful number, since it uses less digits than its factorization.

21280111807845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24066402.

The product of its (nonzero) digits is 286720, while the sum is 48.

The spelling of 21280111807845 in words is "twenty-one trillion, two hundred eighty billion, one hundred eleven million, eight hundred seven thousand, eight hundred forty-five".