99991578 has 16 divisors (see below), whose sum is σ = 201141216. Its totient is φ = 33137520.

The previous prime is 99991561. The next prime is 99991583. The reversal of 99991578 is 87519999.

It is an unprimeable number.

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, 47128 + ... + 49203.

It is an arithmetic number, because the mean of its divisors is an integer number (12571326).

Almost surely, 2^99991578 is an apocalyptic number.

99991578 is an abundant number, since it is smaller than the sum of its proper divisors (101149638).

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

99991578 is a wasteful number, since it uses less digits than its factorization.

99991578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96509.

The product of its digits is 1837080, while the sum is 57.

The square root of 99991578 is about 9999.5788911334. The cubic root of 99991578 is about 464.1458525084.

The spelling of 99991578 in words is "ninety-nine million, nine hundred ninety-one thousand, five hundred seventy-eight".