99999840 has 48 divisors (see below), whose sum is σ = 315001008. Its totient is φ = 26666496.

The previous prime is 99999839. The next prime is 99999847. The reversal of 99999840 is 4899999.

It is a tau number, because it is divible by the number of its divisors (48).

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999847) 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 7 ways as a sum of consecutive naturals, for example, 103687 + ... + 104646.

It is an arithmetic number, because the mean of its divisors is an integer number (6562521).

Almost surely, 2^99999840 is an apocalyptic number.

It is an amenable number.

99999840 is an abundant number, since it is smaller than the sum of its proper divisors (215001168).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

99999840 is a wasteful number, since it uses less digits than its factorization.

99999840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208351 (or 208343 counting only the distinct ones).

The product of its (nonzero) digits is 1889568, while the sum is 57.

The square root of 99999840 is about 9999.9919999968. The cubic root of 99999840 is about 464.1586358097.

The spelling of 99999840 in words is "ninety-nine million, nine hundred ninety-nine thousand, eight hundred forty".