891321866 has 8 divisors (see below), whose sum is σ = 1415628900. Its totient is φ = 419445568.

The previous prime is 891321853. The next prime is 891321887. The reversal of 891321866 is 668123198.

It can be written as a sum of positive squares in 2 ways, for example, as 891321025 + 841 = 29855^2 + 29^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13107641 + ... + 13107708.

Almost surely, 2^891321866 is an apocalyptic number.

891321866 is a deficient number, since it is larger than the sum of its proper divisors (524307034).

891321866 is a wasteful number, since it uses less digits than its factorization.

891321866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26215368.

The product of its digits is 124416, while the sum is 44.

The square root of 891321866 is about 29855.0140847396. The cubic root of 891321866 is about 962.3761544370.

The spelling of 891321866 in words is "eight hundred ninety-one million, three hundred twenty-one thousand, eight hundred sixty-six".