8638891 has 2 divisors, whose sum is σ = 8638892. Its totient is φ = 8638890.

The previous prime is 8638867. The next prime is 8638909. The reversal of 8638891 is 1988368.

It is a happy number.

8638891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 8638891 - 2⁹ = 8638379 is a prime.

It is equal to p₅₇₉₈₈₆ and since 8638891 and 579886 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (8638291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4319445 + 4319446.

It is an arithmetic number, because the mean of its divisors is an integer number (4319446).

Almost surely, 2^8638891 is an apocalyptic number.

8638891 is a deficient number, since it is larger than the sum of its proper divisors (1).

8638891 is an equidigital number, since it uses as much as digits as its factorization.

8638891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 43.

The square root of 8638891 is about 2939.1990405551. The cubic root of 8638891 is about 205.1883337657.

The spelling of 8638891 in words is "eight million, six hundred thirty-eight thousand, eight hundred ninety-one".