81823610491385 has 12 divisors (see below), whose sum is σ = 114219080767908. Its totient is φ = 56107618622496.

The previous prime is 81823610491379. The next prime is 81823610491429. The reversal of 81823610491385 is 58319401632818.

It can be written as a sum of positive squares in 2 ways, for example, as 43512598502464 + 38311011988921 = 6596408^2 + 6189589^2 .

It is not a de Polignac number, because 81823610491385 - 2⁴ = 81823610491369 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166986959942 + ... + 166986960431.

It is an arithmetic number, because the mean of its divisors is an integer number (9518256730659).

Almost surely, 2^{81823610491385} is an apocalyptic number.

It is an amenable number.

81823610491385 is a deficient number, since it is larger than the sum of its proper divisors (32395470276523).

81823610491385 is a wasteful number, since it uses less digits than its factorization.

81823610491385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333973920392 (or 333973920385 counting only the distinct ones).

The product of its (nonzero) digits is 9953280, while the sum is 59.

The spelling of 81823610491385 in words is "eighty-one trillion, eight hundred twenty-three billion, six hundred ten million, four hundred ninety-one thousand, three hundred eighty-five".