20105904899881 has 2 divisors, whose sum is σ = 20105904899882. Its totient is φ = 20105904899880.

The previous prime is 20105904899833. The next prime is 20105904899923. The reversal of 20105904899881 is 18899840950102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18333854058025 + 1772050841856 = 4281805^2 + 1331184^2 .

It is a cyclic number.

It is not a de Polignac number, because 20105904899881 - 2¹¹ = 20105904897833 is a prime.

It is a super-2 number, since 2×20105904899881² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20105904899581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10052952449940 + 10052952449941.

It is an arithmetic number, because the mean of its divisors is an integer number (10052952449941).

Almost surely, 2^{20105904899881} is an apocalyptic number.

It is an amenable number.

20105904899881 is a deficient number, since it is larger than the sum of its proper divisors (1).

20105904899881 is an equidigital number, since it uses as much as digits as its factorization.

20105904899881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14929920, while the sum is 64.

The spelling of 20105904899881 in words is "twenty trillion, one hundred five billion, nine hundred four million, eight hundred ninety-nine thousand, eight hundred eighty-one".