9988215 has 32 divisors (see below), whose sum is σ = 16632000.
Its totient is φ = 5114880.
The previous prime is 9988213. The next prime is 9988229. The reversal of 9988215 is 5128899.
It is a happy number.
9988215 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
9988215 is a nontrivial binomial coefficient, being equal to C(4470, 2).
It is not a de Polignac number, because 9988215 - 21 = 9988213 is a prime.
9988215 is a lucky number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (9988211) by changing a digit.
It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66961 + ... + 67109.
It is an arithmetic number, because the mean of its divisors is an integer number (519750).
Almost surely, 29988215 is an apocalyptic number.
9988215 is the 4469-th triangular number and also the 2235-th hexagonal number.
9988215 is a deficient number, since it is larger than the sum of its proper divisors (6643785).
9988215 is a wasteful number, since it uses less digits than its factorization.
9988215 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 307.
The product of its digits is 51840, while the sum is 42.
The square root of 9988215 is about 3160.4137387374.
The cubic root of 9988215 is about 215.3588023585.
The spelling of 9988215 in words is "nine million, nine hundred eighty-eight thousand, two hundred fifteen".