20138866691091 has 16 divisors (see below), whose sum is σ = 28477721909664. Its totient is φ = 12615538005504.

The previous prime is 20138866691077. The next prime is 20138866691101. The reversal of 20138866691091 is 19019666883102.

It is not a de Polignac number, because 20138866691091 - 2⁷ = 20138866690963 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20138866691291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 322056616 + ... + 322119141.

It is an arithmetic number, because the mean of its divisors is an integer number (1779857619354).

Almost surely, 2^{20138866691091} is an apocalyptic number.

20138866691091 is a deficient number, since it is larger than the sum of its proper divisors (8338855218573).

20138866691091 is a wasteful number, since it uses less digits than its factorization.

20138866691091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644176390.

The product of its (nonzero) digits is 6718464, while the sum is 60.

The spelling of 20138866691091 in words is "twenty trillion, one hundred thirty-eight billion, eight hundred sixty-six million, six hundred ninety-one thousand, ninety-one".