20001100999991 has 2 divisors, whose sum is σ = 20001100999992. Its totient is φ = 20001100999990.

The previous prime is 20001100999967. The next prime is 20001101000029. The reversal of 20001100999991 is 19999900110002.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20001100999991 - 2¹⁸ = 20001100737847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20001100999921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000550499995 + 10000550499996.

It is an arithmetic number, because the mean of its divisors is an integer number (10000550499996).

Almost surely, 2^{20001100999991} is an apocalyptic number.

20001100999991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001100999991 is an equidigital number, since it uses as much as digits as its factorization.

20001100999991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 118098, while the sum is 50.

The spelling of 20001100999991 in words is "twenty trillion, one billion, one hundred million, nine hundred ninety-nine thousand, nine hundred ninety-one".