87815857 has 8 divisors (see below), whose sum is σ = 91189800. Its totient is φ = 84465024.

The previous prime is 87815831. The next prime is 87815873. The reversal of 87815857 is 75851878.

It can be written as a sum of positive squares in 4 ways, for example, as 9511056 + 78304801 = 3084^2 + 8849^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87815857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 87815857.

It is not an unprimeable number, because it can be changed into a prime (87815807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2173 + ... + 13429.

It is an arithmetic number, because the mean of its divisors is an integer number (11398725).

Almost surely, 2^87815857 is an apocalyptic number.

It is an amenable number.

87815857 is a deficient number, since it is larger than the sum of its proper divisors (3373943).

87815857 is a wasteful number, since it uses less digits than its factorization.

87815857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11555.

The product of its digits is 627200, while the sum is 49.

The square root of 87815857 is about 9371.0115249102. The cubic root of 87815857 is about 444.4855511817.

The spelling of 87815857 in words is "eighty-seven million, eight hundred fifteen thousand, eight hundred fifty-seven".