20191791 has 4 divisors (see below), whose sum is σ = 26922392. Its totient is φ = 13461192.

The previous prime is 20191789. The next prime is 20191799. The reversal of 20191791 is 19719102.

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

It is not a de Polignac number, because 20191791 - 2¹ = 20191789 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 (20191799) 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, 3365296 + ... + 3365301.

It is an arithmetic number, because the mean of its divisors is an integer number (6730598).

Almost surely, 2^20191791 is an apocalyptic number.

20191791 is a deficient number, since it is larger than the sum of its proper divisors (6730601).

20191791 is an equidigital number, since it uses as much as digits as its factorization.

20191791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6730600.

The product of its (nonzero) digits is 1134, while the sum is 30.

The square root of 20191791 is about 4493.5276787842. The cubic root of 20191791 is about 272.3066709413.

The spelling of 20191791 in words is "twenty million, one hundred ninety-one thousand, seven hundred ninety-one".