891878891 has 2 divisors, whose sum is σ = 891878892. Its totient is φ = 891878890.

The previous prime is 891878873. The next prime is 891878917. The reversal of 891878891 is 198878198.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 891878891 - 2¹⁰ = 891877867 is a prime.

It is a super-2 number, since 2×891878891² = 1590895912422779762, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 891878891.

It is not a weakly prime, because it can be changed into another prime (891878831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445939445 + 445939446.

It is an arithmetic number, because the mean of its divisors is an integer number (445939446).

Almost surely, 2^891878891 is an apocalyptic number.

891878891 is a deficient number, since it is larger than the sum of its proper divisors (1).

891878891 is an equidigital number, since it uses as much as digits as its factorization.

891878891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2322432, while the sum is 59.

The square root of 891878891 is about 29864.3414626876. The cubic root of 891878891 is about 962.5765893065.

The spelling of 891878891 in words is "eight hundred ninety-one million, eight hundred seventy-eight thousand, eight hundred ninety-one".