20129831991 has 16 divisors (see below), whose sum is σ = 29845900000. Its totient is φ = 13409121024.

The previous prime is 20129831963. The next prime is 20129831999. The reversal of 20129831991 is 19913892102.

It is not a de Polignac number, because 20129831991 - 2²² = 20125637687 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 (20129831999) 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, 264736 + ... + 332181.

It is an arithmetic number, because the mean of its divisors is an integer number (1865368750).

Almost surely, 2^20129831991 is an apocalyptic number.

20129831991 is a deficient number, since it is larger than the sum of its proper divisors (9716068009).

20129831991 is a wasteful number, since it uses less digits than its factorization.

20129831991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598175 (or 598169 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 45.

It can be divided in two parts, 201298 and 31991, that added together give a square (233289 = 483²).

The spelling of 20129831991 in words is "twenty billion, one hundred twenty-nine million, eight hundred thirty-one thousand, nine hundred ninety-one".