921086891 has 2 divisors, whose sum is σ = 921086892. Its totient is φ = 921086890.

The previous prime is 921086879. The next prime is 921086927. The reversal of 921086891 is 198680129.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-921086891 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (921086801) 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, 460543445 + 460543446.

It is an arithmetic number, because the mean of its divisors is an integer number (460543446).

Almost surely, 2^921086891 is an apocalyptic number.

921086891 is a deficient number, since it is larger than the sum of its proper divisors (1).

921086891 is an equidigital number, since it uses as much as digits as its factorization.

921086891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 44.

The square root of 921086891 is about 30349.4133551211. The cubic root of 921086891 is about 972.9716820263.

The spelling of 921086891 in words is "nine hundred twenty-one million, eighty-six thousand, eight hundred ninety-one".