2138205843985 has 4 divisors (see below), whose sum is σ = 2565847012788. Its totient is φ = 1710564675184.

The previous prime is 2138205843973. The next prime is 2138205844007. The reversal of 2138205843985 is 5893485028312.

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 1101651763216 + 1036554080769 = 1049596^2 + 1018113^2 .

It is a cyclic number.

It is not a de Polignac number, because 2138205843985 - 2²³ = 2138197455377 is a prime.

It is a Duffinian 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, 213820584394 + ... + 213820584403.

It is an arithmetic number, because the mean of its divisors is an integer number (641461753197).

Almost surely, 2^{2138205843985} is an apocalyptic number.

It is an amenable number.

2138205843985 is a deficient number, since it is larger than the sum of its proper divisors (427641168803).

2138205843985 is an equidigital number, since it uses as much as digits as its factorization.

2138205843985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427641168802.

The product of its (nonzero) digits is 16588800, while the sum is 58.

The spelling of 2138205843985 in words is "two trillion, one hundred thirty-eight billion, two hundred five million, eight hundred forty-three thousand, nine hundred eighty-five".