84857991 has 4 divisors (see below), whose sum is σ = 113143992. Its totient is φ = 56571992.

The previous prime is 84857953. The next prime is 84858019. The reversal of 84857991 is 19975848.

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 84857991 - 2¹³ = 84849799 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84857911) by changing a digit.

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, 14142996 + ... + 14143001.

It is an arithmetic number, because the mean of its divisors is an integer number (28285998).

Almost surely, 2^84857991 is an apocalyptic number.

84857991 is a deficient number, since it is larger than the sum of its proper divisors (28286001).

84857991 is a wasteful number, since it uses less digits than its factorization.

84857991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28286000.

The product of its digits is 725760, while the sum is 51.

The square root of 84857991 is about 9211.8397185361. The cubic root of 84857991 is about 439.4379721455.

The spelling of 84857991 in words is "eighty-four million, eight hundred fifty-seven thousand, nine hundred ninety-one".