20009717191 has 4 divisors (see below), whose sum is σ = 20348865000. Its totient is φ = 19670569384.

The previous prime is 20009717173. The next prime is 20009717201. The reversal of 20009717191 is 19171790002.

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 20009717191 - 2⁹ = 20009716679 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20009717191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20009717131) 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, 169573816 + ... + 169573933.

It is an arithmetic number, because the mean of its divisors is an integer number (5087216250).

Almost surely, 2^20009717191 is an apocalyptic number.

20009717191 is a deficient number, since it is larger than the sum of its proper divisors (339147809).

20009717191 is an equidigital number, since it uses as much as digits as its factorization.

20009717191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339147808.

The product of its (nonzero) digits is 7938, while the sum is 37.

The spelling of 20009717191 in words is "twenty billion, nine million, seven hundred seventeen thousand, one hundred ninety-one".