20938449818799 has 20 divisors (see below), whose sum is σ = 31488347371800. Its totient is φ = 13865282198640.

The previous prime is 20938449818789. The next prime is 20938449818807. The reversal of 20938449818799 is 99781894483902.

20938449818799 is a `hidden beast` number, since 2 + 0 + 9 + 3 + 8 + 449 + 8 + 1 + 87 + 99 = 666.

It is not a de Polignac number, because 20938449818799 - 2⁸ = 20938449818543 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20938449818789) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 867435517 + ... + 867459654.

It is an arithmetic number, because the mean of its divisors is an integer number (1574417368590).

Almost surely, 2^{20938449818799} is an apocalyptic number.

20938449818799 is a deficient number, since it is larger than the sum of its proper divisors (10549897553001).

20938449818799 is a wasteful number, since it uses less digits than its factorization.

20938449818799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1734895332 (or 1734895323 counting only the distinct ones).

The product of its (nonzero) digits is 2257403904, while the sum is 81.

The spelling of 20938449818799 in words is "twenty trillion, nine hundred thirty-eight billion, four hundred forty-nine million, eight hundred eighteen thousand, seven hundred ninety-nine".