878099561 has 4 divisors (see below), whose sum is σ = 879260292. Its totient is φ = 876938832.

The previous prime is 878099491. The next prime is 878099567. The reversal of 878099561 is 165990878.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 517289536 + 360810025 = 22744^2 + 18995^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-878099561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (878099567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 579230 + ... + 580743.

It is an arithmetic number, because the mean of its divisors is an integer number (219815073).

Almost surely, 2^878099561 is an apocalyptic number.

It is an amenable number.

878099561 is a deficient number, since it is larger than the sum of its proper divisors (1160731).

878099561 is a wasteful number, since it uses less digits than its factorization.

878099561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160730.

The product of its (nonzero) digits is 1088640, while the sum is 53.

The square root of 878099561 is about 29632.7447429360. The cubic root of 878099561 is about 957.5936408088.

The spelling of 878099561 in words is "eight hundred seventy-eight million, ninety-nine thousand, five hundred sixty-one".