99121 has 4 divisors (see below), whose sum is σ = 108144. Its totient is φ = 90100.

The previous prime is 99119. The next prime is 99131. The reversal of 99121 is 12199.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12199 = 11 ⋅1109.

It is a cyclic number.

It is not a de Polignac number, because 99121 - 2¹ = 99119 is a prime.

It is a super-3 number, since 3×99121³ = 2921583339445683, which contains 333 as substring.

It is a Duffinian number.

99121 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 99092 and 99101.

It is not an unprimeable number, because it can be changed into a prime (99131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4495 + ... + 4516.

It is an arithmetic number, because the mean of its divisors is an integer number (27036).

2⁹⁹¹²¹ is an apocalyptic number.

It is an amenable number.

99121 is a deficient number, since it is larger than the sum of its proper divisors (9023).

99121 is a wasteful number, since it uses less digits than its factorization.

99121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9022.

The product of its digits is 162, while the sum is 22.

The square root of 99121 is about 314.8348773564. The cubic root of 99121 is about 46.2794893502.

Subtracting from 99121 its sum of digits (22), we obtain a palindrome (99099).

The spelling of 99121 in words is "ninety-nine thousand, one hundred twenty-one".