2178726318721 has 8 divisors (see below), whose sum is σ = 2255731497000. Its totient is φ = 2101846252800.

The previous prime is 2178726318683. The next prime is 2178726318799. The reversal of 2178726318721 is 1278136278712.

It can be written as a sum of positive squares in 4 ways, for example, as 245583678096 + 1933142640625 = 495564^2 + 1390375^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2178726318721 - 2²⁵ = 2178692764289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5178726318721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31242646 + ... + 31312303.

It is an arithmetic number, because the mean of its divisors is an integer number (281966437125).

Almost surely, 2^{2178726318721} is an apocalyptic number.

It is an amenable number.

2178726318721 is a deficient number, since it is larger than the sum of its proper divisors (77005178279).

2178726318721 is a wasteful number, since it uses less digits than its factorization.

2178726318721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62556179.

The product of its digits is 3161088, while the sum is 55.

The spelling of 2178726318721 in words is "two trillion, one hundred seventy-eight billion, seven hundred twenty-six million, three hundred eighteen thousand, seven hundred twenty-one".