87581917 has 4 divisors (see below), whose sum is σ = 89234460. Its totient is φ = 85929376.

The previous prime is 87581911. The next prime is 87581933. The reversal of 87581917 is 71918578.

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 77810041 + 9771876 = 8821^2 + 3126^2 .

It is a cyclic number.

It is not a de Polignac number, because 87581917 - 2¹⁵ = 87549149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87581911) 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, 826192 + ... + 826297.

It is an arithmetic number, because the mean of its divisors is an integer number (22308615).

Almost surely, 2^87581917 is an apocalyptic number.

It is an amenable number.

87581917 is a deficient number, since it is larger than the sum of its proper divisors (1652543).

87581917 is a wasteful number, since it uses less digits than its factorization.

87581917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1652542.

The product of its digits is 141120, while the sum is 46.

The square root of 87581917 is about 9358.5210904288. The cubic root of 87581917 is about 444.0904994352.

The spelling of 87581917 in words is "eighty-seven million, five hundred eighty-one thousand, nine hundred seventeen".