68394261681 has 14 divisors (see below), whose sum is σ = 102544483970. Its totient is φ = 45596173968.

The previous prime is 68394261653. The next prime is 68394261703. The reversal of 68394261681 is 18616249386.

It can be written as a sum of positive squares in only one way, i.e., 55941710400 + 12452551281 = 236520^2 + 111591^2 .

It is not a de Polignac number, because 68394261681 - 2⁷ = 68394261553 is a prime.

It is a super-2 number, since 2×68394261681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68394961681) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 46908916 + ... + 46910373.

Almost surely, 2^68394261681 is an apocalyptic number.

It is an amenable number.

68394261681 is a deficient number, since it is larger than the sum of its proper divisors (34150222289).

68394261681 is an frugal number, since it uses more digits than its factorization.

68394261681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93819307 (or 93819292 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 54.

The spelling of 68394261681 in words is "sixty-eight billion, three hundred ninety-four million, two hundred sixty-one thousand, six hundred eighty-one".