815899961 has 8 divisors (see below), whose sum is σ = 822441600. Its totient is φ = 809373600.

The previous prime is 815899951. The next prime is 815899969. The reversal of 815899961 is 169998518.

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 815899961 - 2¹⁸ = 815637817 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 815899897 and 815899906.

It is not an unprimeable number, because it can be changed into a prime (815899969) 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 in 7 ways as a sum of consecutive naturals, for example, 118820 + ... + 125498.

It is an arithmetic number, because the mean of its divisors is an integer number (102805200).

Almost surely, 2^815899961 is an apocalyptic number.

It is an amenable number.

815899961 is a deficient number, since it is larger than the sum of its proper divisors (6541639).

815899961 is a wasteful number, since it uses less digits than its factorization.

815899961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7639.

The product of its digits is 1399680, while the sum is 56.

The square root of 815899961 is about 28563.9626277588. The cubic root of 815899961 is about 934.4275566027.

The spelling of 815899961 in words is "eight hundred fifteen million, eight hundred ninety-nine thousand, nine hundred sixty-one".