815559361 has 2 divisors, whose sum is σ = 815559362. Its totient is φ = 815559360.

The previous prime is 815559359. The next prime is 815559379. The reversal of 815559361 is 163955518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 541027600 + 274531761 = 23260^2 + 16569^2 .

It is a cyclic number.

It is not a de Polignac number, because 815559361 - 2¹ = 815559359 is a prime.

Together with 815559359, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (815559161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407779680 + 407779681.

It is an arithmetic number, because the mean of its divisors is an integer number (407779681).

Almost surely, 2^815559361 is an apocalyptic number.

It is an amenable number.

815559361 is a deficient number, since it is larger than the sum of its proper divisors (1).

815559361 is an equidigital number, since it uses as much as digits as its factorization.

815559361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 162000, while the sum is 43.

The square root of 815559361 is about 28557.9999474753. Note that the first 4 decimals coincide. The cubic root of 815559361 is about 934.2975119329.

The spelling of 815559361 in words is "eight hundred fifteen million, five hundred fifty-nine thousand, three hundred sixty-one".