891700991 has 4 divisors (see below), whose sum is σ = 908525592. Its totient is φ = 874876392.

The previous prime is 891700969. The next prime is 891701003. The reversal of 891700991 is 199007198.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 891700991 - 2¹⁰ = 891699967 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 (891600991) 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, 8412221 + ... + 8412326.

It is an arithmetic number, because the mean of its divisors is an integer number (227131398).

Almost surely, 2^891700991 is an apocalyptic number.

891700991 is a deficient number, since it is larger than the sum of its proper divisors (16824601).

891700991 is a wasteful number, since it uses less digits than its factorization.

891700991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16824600.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 891700991 is about 29861.3628456573. The cubic root of 891700991 is about 962.5125844422.

The spelling of 891700991 in words is "eight hundred ninety-one million, seven hundred thousand, nine hundred ninety-one".