2158121 has 4 divisors (see below), whose sum is σ = 2466432. Its totient is φ = 1849812.

The previous prime is 2158103. The next prime is 2158129. The reversal of 2158121 is 1218512.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 2158121 - 2¹⁰ = 2157097 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a junction number, because it is equal to n+sod(n) for n = 2158093 and 2158102.

It is not an unprimeable number, because it can be changed into a prime (2158129) 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, 154145 + ... + 154158.

It is an arithmetic number, because the mean of its divisors is an integer number (616608).

2^2158121 is an apocalyptic number.

It is an amenable number.

2158121 is a deficient number, since it is larger than the sum of its proper divisors (308311).

2158121 is an equidigital number, since it uses as much as digits as its factorization.

2158121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308310.

The product of its digits is 160, while the sum is 20.

The square root of 2158121 is about 1469.0544578061. The cubic root of 2158121 is about 129.2285873538.

Subtracting from 2158121 its product of digits (160), we obtain a square (2157961 = 1469²).

The spelling of 2158121 in words is "two million, one hundred fifty-eight thousand, one hundred twenty-one".