68644236865 has 16 divisors (see below), whose sum is σ = 85471564752. Its totient is φ = 52880338944.

The previous prime is 68644236863. The next prime is 68644236919. The reversal of 68644236865 is 56863244686.

It can be written as a sum of positive squares in 8 ways, for example, as 10043447089 + 58600789776 = 100217^2 + 242076^2 .

It is a cyclic number.

It is not a de Polignac number, because 68644236865 - 2¹ = 68644236863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68644236863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1894684 + ... + 1930573.

It is an arithmetic number, because the mean of its divisors is an integer number (5341972797).

Almost surely, 2^68644236865 is an apocalyptic number.

It is an amenable number.

68644236865 is a deficient number, since it is larger than the sum of its proper divisors (16827327887).

68644236865 is a wasteful number, since it uses less digits than its factorization.

68644236865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3825396.

The product of its digits is 39813120, while the sum is 58.

The spelling of 68644236865 in words is "sixty-eight billion, six hundred forty-four million, two hundred thirty-six thousand, eight hundred sixty-five".