891442661 has 4 divisors (see below), whose sum is σ = 893560524. Its totient is φ = 889324800.

The previous prime is 891442631. The next prime is 891442663. The reversal of 891442661 is 166244198.

891442661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166244198 = 2 ⋅83122099.

It can be written as a sum of positive squares in 2 ways, for example, as 14394436 + 877048225 = 3794^2 + 29615^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-891442661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891442663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1058300 + ... + 1059141.

It is an arithmetic number, because the mean of its divisors is an integer number (223390131).

Almost surely, 2^891442661 is an apocalyptic number.

It is an amenable number.

891442661 is a deficient number, since it is larger than the sum of its proper divisors (2117863).

891442661 is a wasteful number, since it uses less digits than its factorization.

891442661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2117862.

The product of its digits is 82944, while the sum is 41.

The square root of 891442661 is about 29857.0370432165. The cubic root of 891442661 is about 962.4196273136.

The spelling of 891442661 in words is "eight hundred ninety-one million, four hundred forty-two thousand, six hundred sixty-one".