20938191191 has 4 divisors (see below), whose sum is σ = 21088825800. Its totient is φ = 20787556584.

The previous prime is 20938191187. The next prime is 20938191217. The reversal of 20938191191 is 19119183902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20938191191 - 2² = 20938191187 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20938191181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75317096 + ... + 75317373.

It is an arithmetic number, because the mean of its divisors is an integer number (5272206450).

Almost surely, 2^20938191191 is an apocalyptic number.

20938191191 is a deficient number, since it is larger than the sum of its proper divisors (150634609).

20938191191 is a wasteful number, since it uses less digits than its factorization.

20938191191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150634608.

The product of its (nonzero) digits is 34992, while the sum is 44.

The spelling of 20938191191 in words is "twenty billion, nine hundred thirty-eight million, one hundred ninety-one thousand, one hundred ninety-one".