87718991 has 4 divisors (see below), whose sum is σ = 92335800. Its totient is φ = 83102184.

The previous prime is 87718973. The next prime is 87718999. The reversal of 87718991 is 19981778.

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 87718991 - 2¹⁴ = 87702607 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 (87718999) 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, 2308376 + ... + 2308413.

It is an arithmetic number, because the mean of its divisors is an integer number (23083950).

Almost surely, 2^87718991 is an apocalyptic number.

87718991 is a deficient number, since it is larger than the sum of its proper divisors (4616809).

87718991 is a wasteful number, since it uses less digits than its factorization.

87718991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4616808.

The product of its digits is 254016, while the sum is 50.

The square root of 87718991 is about 9365.8417133753. The cubic root of 87718991 is about 444.3220599114.

The spelling of 87718991 in words is "eighty-seven million, seven hundred eighteen thousand, nine hundred ninety-one".