2138628978085 has 4 divisors (see below), whose sum is σ = 2566354773708. Its totient is φ = 1710903182464.

The previous prime is 2138628978061. The next prime is 2138628978091. The reversal of 2138628978085 is 5808798268312.

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 1099073366689 + 1039555611396 = 1048367^2 + 1019586^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2138628978085 is a prime.

It is a Smith number, since the sum of its digits (67) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 2138628978085.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213862897804 + ... + 213862897813.

It is an arithmetic number, because the mean of its divisors is an integer number (641588693427).

Almost surely, 2^{2138628978085} is an apocalyptic number.

It is an amenable number.

2138628978085 is a deficient number, since it is larger than the sum of its proper divisors (427725795623).

2138628978085 is an equidigital number, since it uses as much as digits as its factorization.

2138628978085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427725795622.

The product of its (nonzero) digits is 92897280, while the sum is 67.

The spelling of 2138628978085 in words is "two trillion, one hundred thirty-eight billion, six hundred twenty-eight million, nine hundred seventy-eight thousand, eighty-five".