847997891 has 6 divisors (see below), whose sum is σ = 918246420. Its totient is φ = 782767128.

The previous prime is 847997881. The next prime is 847997921. The reversal of 847997891 is 198799748.

It is not a de Polignac number, because 847997891 - 2¹⁴ = 847981507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (847997831) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2508701 + ... + 2509038.

It is an arithmetic number, because the mean of its divisors is an integer number (153041070).

Almost surely, 2^847997891 is an apocalyptic number.

847997891 is a deficient number, since it is larger than the sum of its proper divisors (70248529).

847997891 is a wasteful number, since it uses less digits than its factorization.

847997891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5017765 (or 5017752 counting only the distinct ones).

The product of its digits is 9144576, while the sum is 62.

The square root of 847997891 is about 29120.4033454209. The cubic root of 847997891 is about 946.5239135541.

The spelling of 847997891 in words is "eight hundred forty-seven million, nine hundred ninety-seven thousand, eight hundred ninety-one".