20844578983817 has 4 divisors (see below), whose sum is σ = 20866046110416. Its totient is φ = 20823111857220.

The previous prime is 20844578983799. The next prime is 20844578983849. The reversal of 20844578983817 is 71838987544802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20844578983817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20844578983897) 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, 10733561843 + ... + 10733563784.

It is an arithmetic number, because the mean of its divisors is an integer number (5216511527604).

Almost surely, 2^{20844578983817} is an apocalyptic number.

It is an amenable number.

20844578983817 is a deficient number, since it is larger than the sum of its proper divisors (21467126599).

20844578983817 is an equidigital number, since it uses as much as digits as its factorization.

20844578983817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21467126598.

The product of its (nonzero) digits is 867041280, while the sum is 74.

The spelling of 20844578983817 in words is "twenty trillion, eight hundred forty-four billion, five hundred seventy-eight million, nine hundred eighty-three thousand, eight hundred seventeen".