20938449818893 has 2 divisors, whose sum is σ = 20938449818894. Its totient is φ = 20938449818892.

The previous prime is 20938449818857. The next prime is 20938449818917. The reversal of 20938449818893 is 39881894483902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20645636800009 + 292813018884 = 4543747^2 + 541122^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20938449818893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20938449818593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10469224909446 + 10469224909447.

It is an arithmetic number, because the mean of its divisors is an integer number (10469224909447).

Almost surely, 2^{20938449818893} is an apocalyptic number.

It is an amenable number.

20938449818893 is a deficient number, since it is larger than the sum of its proper divisors (1).

20938449818893 is an equidigital number, since it uses as much as digits as its factorization.

20938449818893 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 859963392, while the sum is 76.

The spelling of 20938449818893 in words is "twenty trillion, nine hundred thirty-eight billion, four hundred forty-nine million, eight hundred eighteen thousand, eight hundred ninety-three".