20911891199 has 16 divisors (see below), whose sum is σ = 22461281568. Its totient is φ = 19398362112.

The previous prime is 20911891171. The next prime is 20911891201. The reversal of 20911891199 is 99119811902.

It is a cyclic number.

It is not a de Polignac number, because 20911891199 - 2¹⁶ = 20911825663 is a prime.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20911851199) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2013929 + ... + 2024285.

It is an arithmetic number, because the mean of its divisors is an integer number (1403830098).

Almost surely, 2^20911891199 is an apocalyptic number.

20911891199 is a deficient number, since it is larger than the sum of its proper divisors (1549390369).

20911891199 is a wasteful number, since it uses less digits than its factorization.

20911891199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12074.

The product of its (nonzero) digits is 104976, while the sum is 50.

The spelling of 20911891199 in words is "twenty billion, nine hundred eleven million, eight hundred ninety-one thousand, one hundred ninety-nine".