815808085385 has 32 divisors (see below), whose sum is σ = 1039620824352. Its totient is φ = 612440801280.

The previous prime is 815808085363. The next prime is 815808085387. The reversal of 815808085385 is 583580808518.

It can be written as a sum of positive squares in 16 ways, for example, as 104179181824 + 711628903561 = 322768^2 + 843581^2 .

It is a de Polignac number, because none of the positive numbers 2^k-815808085385 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (815808085387) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 113413349 + ... + 113420541.

It is an arithmetic number, because the mean of its divisors is an integer number (32488150761).

Almost surely, 2^815808085385 is an apocalyptic number.

815808085385 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

815808085385 is a deficient number, since it is larger than the sum of its proper divisors (223812738967).

815808085385 is a wasteful number, since it uses less digits than its factorization.

815808085385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10973.

The product of its (nonzero) digits is 12288000, while the sum is 59.

The spelling of 815808085385 in words is "eight hundred fifteen billion, eight hundred eight million, eighty-five thousand, three hundred eighty-five".