81385471439 has 8 divisors (see below), whose sum is σ = 82611462720. Its totient is φ = 80164375200.

The previous prime is 81385471429. The next prime is 81385471487. The reversal of 81385471439 is 93417458318.

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 81385471439 - 2¹² = 81385467343 is a prime.

It is a super-2 number, since 2×81385471439² (a number of 23 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 (81385471429) 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, 1190252 + ... + 1256769.

It is an arithmetic number, because the mean of its divisors is an integer number (10326432840).

Almost surely, 2^81385471439 is an apocalyptic number.

81385471439 is a deficient number, since it is larger than the sum of its proper divisors (1225991281).

81385471439 is a wasteful number, since it uses less digits than its factorization.

81385471439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2447521.

The product of its digits is 2903040, while the sum is 53.

The spelling of 81385471439 in words is "eighty-one billion, three hundred eighty-five million, four hundred seventy-one thousand, four hundred thirty-nine".