20896915717 has 4 divisors (see below), whose sum is σ = 20963679340. Its totient is φ = 20830152096.

The previous prime is 20896915709. The next prime is 20896915751. The reversal of 20896915717 is 71751969802.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2386224801 + 18510690916 = 48849^2 + 136054^2 .

It is a cyclic number.

It is not a de Polignac number, because 20896915717 - 2³ = 20896915709 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 (20896915757) 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, 33381342 + ... + 33381967.

It is an arithmetic number, because the mean of its divisors is an integer number (5240919835).

Almost surely, 2^20896915717 is an apocalyptic number.

It is an amenable number.

20896915717 is a deficient number, since it is larger than the sum of its proper divisors (66763623).

20896915717 is an equidigital number, since it uses as much as digits as its factorization.

20896915717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66763622.

The product of its (nonzero) digits is 1905120, while the sum is 55.

The spelling of 20896915717 in words is "twenty billion, eight hundred ninety-six million, nine hundred fifteen thousand, seven hundred seventeen".