918121 has 4 divisors (see below), whose sum is σ = 930772. Its totient is φ = 905472.

The previous prime is 918109. The next prime is 918131. The reversal of 918121 is 121819.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121819 = 43 ⋅2833.

It can be written as a sum of positive squares in 2 ways, for example, as 705600 + 212521 = 840^2 + 461^2 .

It is a cyclic number.

It is not a de Polignac number, because 918121 - 2⁵ = 918089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 918092 and 918101.

It is not an unprimeable number, because it can be changed into a prime (918131) 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, 6216 + ... + 6361.

It is an arithmetic number, because the mean of its divisors is an integer number (232693).

2⁹¹⁸¹²¹ is an apocalyptic number.

It is an amenable number.

918121 is a deficient number, since it is larger than the sum of its proper divisors (12651).

918121 is a wasteful number, since it uses less digits than its factorization.

918121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12650.

The product of its digits is 144, while the sum is 22.

The square root of 918121 is about 958.1863075624. The cubic root of 918121 is about 97.1926239273.

The spelling of 918121 in words is "nine hundred eighteen thousand, one hundred twenty-one".