87191887 has 2 divisors, whose sum is σ = 87191888. Its totient is φ = 87191886.

The previous prime is 87191843. The next prime is 87191899. The reversal of 87191887 is 78819178.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87191887 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 87191887.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87191807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43595943 + 43595944.

It is an arithmetic number, because the mean of its divisors is an integer number (43595944).

Almost surely, 2^87191887 is an apocalyptic number.

87191887 is a deficient number, since it is larger than the sum of its proper divisors (1).

87191887 is an equidigital number, since it uses as much as digits as its factorization.

87191887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 225792, while the sum is 49.

The square root of 87191887 is about 9337.6596104163. The cubic root of 87191887 is about 443.4302932379.

The spelling of 87191887 in words is "eighty-seven million, one hundred ninety-one thousand, eight hundred eighty-seven".