2121257 has 4 divisors (see below), whose sum is σ = 2125200. Its totient is φ = 2117316.

The previous prime is 2121253. The next prime is 2121271. The reversal of 2121257 is 7521212.

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 2121257 - 2² = 2121253 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121253) 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, 1007 + ... + 2292.

It is an arithmetic number, because the mean of its divisors is an integer number (531300).

2^2121257 is an apocalyptic number.

It is an amenable number.

2121257 is a deficient number, since it is larger than the sum of its proper divisors (3943).

2121257 is an equidigital number, since it uses as much as digits as its factorization.

2121257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3942.

The product of its digits is 280, while the sum is 20.

The square root of 2121257 is about 1456.4535694625. The cubic root of 2121257 is about 128.4885504088.

Adding to 2121257 its reverse (7521212), we get a palindrome (9642469).

The spelling of 2121257 in words is "two million, one hundred twenty-one thousand, two hundred fifty-seven".