9999855 has 20 divisors (see below), whose sum is σ = 17926392. Its totient is φ = 5333040.

The previous prime is 9999823. The next prime is 9999863. The reversal of 9999855 is 5589999.

It is not a de Polignac number, because 9999855 - 2⁵ = 9999823 is a prime.

9999855 is a lucky number.

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 11941 + ... + 12750.

Almost surely, 2^9999855 is an apocalyptic number.

9999855 is a deficient number, since it is larger than the sum of its proper divisors (7926537).

9999855 is a wasteful number, since it uses less digits than its factorization.

9999855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24708 (or 24699 counting only the distinct ones).

The product of its digits is 1312200, while the sum is 54.

The square root of 9999855 is about 3162.2547335722. The cubic root of 9999855 is about 215.4424276881.

The spelling of 9999855 in words is "nine million, nine hundred ninety-nine thousand, eight hundred fifty-five".