9915121 has 2 divisors, whose sum is σ = 9915122. Its totient is φ = 9915120.

The previous prime is 9915119. The next prime is 9915137. The reversal of 9915121 is 1215199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6305121 + 3610000 = 2511^2 + 1900^2 .

It is a cyclic number.

It is not a de Polignac number, because 9915121 - 2¹ = 9915119 is a prime.

Together with 9915119, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 9915121.

It is not a weakly prime, because it can be changed into another prime (9915161) 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 as a sum of consecutive naturals, namely, 4957560 + 4957561.

It is an arithmetic number, because the mean of its divisors is an integer number (4957561).

Almost surely, 2^9915121 is an apocalyptic number.

It is an amenable number.

9915121 is a deficient number, since it is larger than the sum of its proper divisors (1).

9915121 is an equidigital number, since it uses as much as digits as its factorization.

9915121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 810, while the sum is 28.

The square root of 9915121 is about 3148.8285123201. The cubic root of 9915121 is about 214.8321820059.

The spelling of 9915121 in words is "nine million, nine hundred fifteen thousand, one hundred twenty-one".