68931665281 has 8 divisors (see below), whose sum is σ = 69840168840. Its totient is φ = 68028398592.

The previous prime is 68931665273. The next prime is 68931665339. The reversal of 68931665281 is 18256613986.

It can be written as a sum of positive squares in 4 ways, for example, as 6803610256 + 62128055025 = 82484^2 + 249255^2 .

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 68931665281 - 2³ = 68931665273 is a prime.

It is a super-2 number, since 2×68931665281² (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 (68931665081) 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, 1282716 + ... + 1335373.

It is an arithmetic number, because the mean of its divisors is an integer number (8730021105).

Almost surely, 2^68931665281 is an apocalyptic number.

It is an amenable number.

68931665281 is a deficient number, since it is larger than the sum of its proper divisors (908503559).

68931665281 is a wasteful number, since it uses less digits than its factorization.

68931665281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2618435.

The product of its digits is 3732480, while the sum is 55.

The spelling of 68931665281 in words is "sixty-eight billion, nine hundred thirty-one million, six hundred sixty-five thousand, two hundred eighty-one".