20051791 has 4 divisors (see below), whose sum is σ = 20923632. Its totient is φ = 19179952.

The previous prime is 20051767. The next prime is 20051813. The reversal of 20051791 is 19715002.

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 20051791 - 2⁷ = 20051663 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 (20051711) 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, 435886 + ... + 435931.

It is an arithmetic number, because the mean of its divisors is an integer number (5230908).

Almost surely, 2^20051791 is an apocalyptic number.

20051791 is a deficient number, since it is larger than the sum of its proper divisors (871841).

20051791 is an equidigital number, since it uses as much as digits as its factorization.

20051791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 871840.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 20051791 is about 4477.9226210376. The cubic root of 20051791 is about 271.6758637073.

Adding to 20051791 its reverse (19715002), we get a palindrome (39766793).

The spelling of 20051791 in words is "twenty million, fifty-one thousand, seven hundred ninety-one".