87117891 has 16 divisors (see below), whose sum is σ = 133387008. Its totient is φ = 49543200.

The previous prime is 87117857. The next prime is 87117893. The reversal of 87117891 is 19871178.

It is a happy number.

It is not a de Polignac number, because 87117891 - 2⁷ = 87117763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (87117893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5400 + ... + 14261.

It is an arithmetic number, because the mean of its divisors is an integer number (8336688).

Almost surely, 2^87117891 is an apocalyptic number.

87117891 is a deficient number, since it is larger than the sum of its proper divisors (46269117).

87117891 is a wasteful number, since it uses less digits than its factorization.

87117891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19882.

The product of its digits is 28224, while the sum is 42.

The square root of 87117891 is about 9333.6965345998. The cubic root of 87117891 is about 443.3048176708.

The spelling of 87117891 in words is "eighty-seven million, one hundred seventeen thousand, eight hundred ninety-one".