2156717742517 has 4 divisors (see below), whose sum is σ = 2322619107340. Its totient is φ = 1990816377696.

The previous prime is 2156717742499. The next prime is 2156717742523. The reversal of 2156717742517 is 7152477176512.

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 438295637521 + 1718422104996 = 662039^2 + 1310886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2156717742517 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 (2156717742017) 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, 82950682392 + ... + 82950682417.

It is an arithmetic number, because the mean of its divisors is an integer number (580654776835).

Almost surely, 2^{2156717742517} is an apocalyptic number.

It is an amenable number.

2156717742517 is a deficient number, since it is larger than the sum of its proper divisors (165901364823).

2156717742517 is a wasteful number, since it uses less digits than its factorization.

2156717742517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165901364822.

The product of its digits is 5762400, while the sum is 55.

The spelling of 2156717742517 in words is "two trillion, one hundred fifty-six billion, seven hundred seventeen million, seven hundred forty-two thousand, five hundred seventeen".