84639999 has 8 divisors (see below), whose sum is σ = 112902400. Its totient is φ = 56402136.

The previous prime is 84639967. The next prime is 84640027. The reversal of 84639999 is 99993648.

It is a Cunningham number, because it is equal to 9200²-1.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 84639999 - 2⁵ = 84639967 is a prime.

It is a Duffinian number.

84639999 is a modest number, since divided by 9999 gives 8463 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84639959) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4602 + ... + 13800.

It is an arithmetic number, because the mean of its divisors is an integer number (14112800).

Almost surely, 2^84639999 is an apocalyptic number.

84639999 is a deficient number, since it is larger than the sum of its proper divisors (28262401).

84639999 is a wasteful number, since it uses less digits than its factorization.

84639999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12269.

The product of its digits is 3779136, while the sum is 57.

The square root of 84639999 is about 9199.9999456522. Note that the first 4 decimals coincide. The cubic root of 84639999 is about 439.0613582009.

The spelling of 84639999 in words is "eighty-four million, six hundred thirty-nine thousand, nine hundred ninety-nine".