84107991 has 16 divisors (see below), whose sum is σ = 126286848. Its totient is φ = 49329600.

The previous prime is 84107977. The next prime is 84108019. The reversal of 84107991 is 19970148.

It is a happy number.

It is not a de Polignac number, because 84107991 - 2⁹ = 84107479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84107921) 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 15 ways as a sum of consecutive naturals, for example, 40086 + ... + 42131.

It is an arithmetic number, because the mean of its divisors is an integer number (7892928).

Almost surely, 2^84107991 is an apocalyptic number.

84107991 is a deficient number, since it is larger than the sum of its proper divisors (42178857).

84107991 is a wasteful number, since it uses less digits than its factorization.

84107991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82262.

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 84107991 is about 9171.0408896700. The cubic root of 84107991 is about 438.1395116557.

The spelling of 84107991 in words is "eighty-four million, one hundred seven thousand, nine hundred ninety-one".