891987071 has 4 divisors (see below), whose sum is σ = 901182912. Its totient is φ = 882791232.

The previous prime is 891987067. The next prime is 891987101. The reversal of 891987071 is 170789198.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 170789198 = 2 ⋅85394599.

It is a cyclic number.

It is not a de Polignac number, because 891987071 - 2² = 891987067 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 (891987871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4597775 + ... + 4597968.

It is an arithmetic number, because the mean of its divisors is an integer number (225295728).

Almost surely, 2^891987071 is an apocalyptic number.

891987071 is a deficient number, since it is larger than the sum of its proper divisors (9195841).

891987071 is an equidigital number, since it uses as much as digits as its factorization.

891987071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9195840.

The product of its (nonzero) digits is 254016, while the sum is 50.

The square root of 891987071 is about 29866.1525978824. The cubic root of 891987071 is about 962.6155061470.

It can be divided in two parts, 89198 and 7071, that added together give a palindrome (96269).

The spelling of 891987071 in words is "eight hundred ninety-one million, nine hundred eighty-seven thousand, seventy-one".