2157217 has 4 divisors (see below), whose sum is σ = 2193840. Its totient is φ = 2120596.

The previous prime is 2157209. The next prime is 2157229. The reversal of 2157217 is 7127512.

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 2157217 - 2³ = 2157209 is a prime.

It is a Duffinian number.

2157217 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 2157191 and 2157200.

It is not an unprimeable number, because it can be changed into a prime (2157247) 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, 18223 + ... + 18340.

It is an arithmetic number, because the mean of its divisors is an integer number (548460).

2^2157217 is an apocalyptic number.

It is an amenable number.

2157217 is a deficient number, since it is larger than the sum of its proper divisors (36623).

2157217 is an equidigital number, since it uses as much as digits as its factorization.

2157217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36622.

The product of its digits is 980, while the sum is 25.

The square root of 2157217 is about 1468.7467446772. The cubic root of 2157217 is about 129.2105409516.

The spelling of 2157217 in words is "two million, one hundred fifty-seven thousand, two hundred seventeen".