9872121 has 16 divisors (see below), whose sum is σ = 15928704. Its totient is φ = 5309184.

The previous prime is 9872117. The next prime is 9872123. The reversal of 9872121 is 1212789.

It is not a de Polignac number, because 9872121 - 2² = 9872117 is a prime.

It is an alternating number because its digits alternate between odd and even.

9872121 is a modest number, since divided by 2121 gives 987 as remainder.

It is not an unprimeable number, because it can be changed into a prime (9872123) 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 15 ways as a sum of consecutive naturals, for example, 13470 + ... + 14183.

It is an arithmetic number, because the mean of its divisors is an integer number (995544).

Almost surely, 2^9872121 is an apocalyptic number.

It is an amenable number.

9872121 is a deficient number, since it is larger than the sum of its proper divisors (6056583).

9872121 is a wasteful number, since it uses less digits than its factorization.

9872121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27680.

The product of its digits is 2016, while the sum is 30.

The square root of 9872121 is about 3141.9931572172. The cubic root of 9872121 is about 214.5211698234.

The spelling of 9872121 in words is "nine million, eight hundred seventy-two thousand, one hundred twenty-one".