815197985 has 24 divisors (see below), whose sum is σ = 1137425856. Its totient is φ = 549436320.

The previous prime is 815197973. The next prime is 815197987. The reversal of 815197985 is 589791518.

It is a happy number.

815197985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 815197985 - 2⁴ = 815197969 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (815197987) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 118490 + ... + 125180.

It is an arithmetic number, because the mean of its divisors is an integer number (47392744).

Almost surely, 2^815197985 is an apocalyptic number.

It is an amenable number.

815197985 is a deficient number, since it is larger than the sum of its proper divisors (322227871).

815197985 is an equidigital number, since it uses as much as digits as its factorization.

815197985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6821 (or 6762 counting only the distinct ones).

The product of its digits is 907200, while the sum is 53.

The square root of 815197985 is about 28551.6721927105. The cubic root of 815197985 is about 934.1594951742.

The spelling of 815197985 in words is "eight hundred fifteen million, one hundred ninety-seven thousand, nine hundred eighty-five".