20172310391 has 4 divisors (see below), whose sum is σ = 20176963800. Its totient is φ = 20167656984.

The previous prime is 20172310363. The next prime is 20172310427. The reversal of 20172310391 is 19301327102.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20172310391 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 (20172310331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2320196 + ... + 2328873.

It is an arithmetic number, because the mean of its divisors is an integer number (5044240950).

Almost surely, 2^20172310391 is an apocalyptic number.

20172310391 is a deficient number, since it is larger than the sum of its proper divisors (4653409).

20172310391 is an equidigital number, since it uses as much as digits as its factorization.

20172310391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4653408.

The product of its (nonzero) digits is 2268, while the sum is 29.

Adding to 20172310391 its reverse (19301327102), we get a palindrome (39473637493).

The spelling of 20172310391 in words is "twenty billion, one hundred seventy-two million, three hundred ten thousand, three hundred ninety-one".