9999881 has 4 divisors (see below), whose sum is σ = 10188612.
Its totient is φ = 9811152.
The previous prime is 9999877. The next prime is 9999883. The reversal of 9999881 is 1889999.
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in 2 ways, for example, as 8462281 + 1537600 = 2909^2 + 1240^2
It is a cyclic number.
It is not a de Polignac number, because 9999881 - 22 = 9999877 is a prime.
It is a super-2 number, since 2×99998812 = 199995240028322, which contains 22 as substring.
It is a Harshad number since it is a multiple of its sum of digits (53), and also a Moran number because the ratio is a prime number: 188677 = 9999881 / (9 + 9 + 9 + 9 + 8 + 8 + 1).
It is a Duffinian number.
It is a nialpdrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (9999883) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94286 + ... + 94391.
It is an arithmetic number, because the mean of its divisors is an integer number (2547153).
Almost surely, 29999881 is an apocalyptic number.
It is an amenable number.
9999881 is a deficient number, since it is larger than the sum of its proper divisors (188731).
9999881 is a wasteful number, since it uses less digits than its factorization.
9999881 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 188730.
The product of its digits is 419904, while the sum is 53.
The square root of 9999881 is about 3162.2588445603.
The cubic root of 9999881 is about 215.4426144074.
The spelling of 9999881 in words is "nine million, nine hundred ninety-nine thousand, eight hundred eighty-one".