87809891 has 4 divisors (see below), whose sum is σ = 94564512. Its totient is φ = 81055272.

The previous prime is 87809873. The next prime is 87809899. The reversal of 87809891 is 19890878.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 87809891 - 2¹⁰ = 87808867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87809899) 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, 3377291 + ... + 3377316.

It is an arithmetic number, because the mean of its divisors is an integer number (23641128).

Almost surely, 2^87809891 is an apocalyptic number.

87809891 is a deficient number, since it is larger than the sum of its proper divisors (6754621).

87809891 is a wasteful number, since it uses less digits than its factorization.

87809891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6754620.

The product of its (nonzero) digits is 290304, while the sum is 50.

The square root of 87809891 is about 9370.6931974107. The cubic root of 87809891 is about 444.4754851908.

The spelling of 87809891 in words is "eighty-seven million, eight hundred nine thousand, eight hundred ninety-one".