81389041679399 has 4 divisors (see below), whose sum is σ = 81676635466536. Its totient is φ = 81101447892264.

The previous prime is 81389041679389. The next prime is 81389041679417. The reversal of 81389041679399 is 99397614098318.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81389041679399 - 2²⁰ = 81389040630823 is a prime.

It is a super-2 number, since 2×81389041679399² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81389041679329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 143796893144 + ... + 143796893709.

It is an arithmetic number, because the mean of its divisors is an integer number (20419158866634).

Almost surely, 2^{81389041679399} is an apocalyptic number.

81389041679399 is a deficient number, since it is larger than the sum of its proper divisors (287593787137).

81389041679399 is a wasteful number, since it uses less digits than its factorization.

81389041679399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287593787136.

The product of its (nonzero) digits is 634894848, while the sum is 77.

The spelling of 81389041679399 in words is "eighty-one trillion, three hundred eighty-nine billion, forty-one million, six hundred seventy-nine thousand, three hundred ninety-nine".