8991121 has 4 divisors (see below), whose sum is σ = 9080244. Its totient is φ = 8902000.

The previous prime is 8991097. The next prime is 8991127. The reversal of 8991121 is 1211998.

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 7700625 + 1290496 = 2775^2 + 1136^2 .

It is a cyclic number.

It is not a de Polignac number, because 8991121 - 2⁵ = 8991089 is a prime.

It is a Duffinian number.

8991121 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8991127) 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, 44410 + ... + 44611.

It is an arithmetic number, because the mean of its divisors is an integer number (2270061).

Almost surely, 2^8991121 is an apocalyptic number.

It is an amenable number.

8991121 is a deficient number, since it is larger than the sum of its proper divisors (89123).

8991121 is a wasteful number, since it uses less digits than its factorization.

8991121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89122.

The product of its digits is 1296, while the sum is 31.

The square root of 8991121 is about 2998.5198015021. The cubic root of 8991121 is about 207.9399558564.

The spelling of 8991121 in words is "eight million, nine hundred ninety-one thousand, one hundred twenty-one".