68378516783021 has 4 divisors (see below), whose sum is σ = 68408494214844. Its totient is φ = 68348539351200.

The previous prime is 68378516782997. The next prime is 68378516783033. The reversal of 68378516783021 is 12038761587386.

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 41259887704996 + 27118629078025 = 6423386^2 + 5207555^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68378516783021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68378516783821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14988712490 + ... + 14988717051.

It is an arithmetic number, because the mean of its divisors is an integer number (17102123553711).

Almost surely, 2^{68378516783021} is an apocalyptic number.

It is an amenable number.

68378516783021 is a deficient number, since it is larger than the sum of its proper divisors (29977431823).

68378516783021 is a wasteful number, since it uses less digits than its factorization.

68378516783021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29977431822.

The product of its (nonzero) digits is 81285120, while the sum is 65.

The spelling of 68378516783021 in words is "sixty-eight trillion, three hundred seventy-eight billion, five hundred sixteen million, seven hundred eighty-three thousand, twenty-one".