2217421 has 2 divisors, whose sum is σ = 2217422. Its totient is φ = 2217420.

The previous prime is 2217409. The next prime is 2217443. The reversal of 2217421 is 1247122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2102500 + 114921 = 1450^2 + 339^2 .

It is a cyclic number.

It is not a de Polignac number, because 2217421 - 2⁹ = 2216909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2217491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1108710 + 1108711.

It is an arithmetic number, because the mean of its divisors is an integer number (1108711).

2^2217421 is an apocalyptic number.

It is an amenable number.

2217421 is a deficient number, since it is larger than the sum of its proper divisors (1).

2217421 is an equidigital number, since it uses as much as digits as its factorization.

2217421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 224, while the sum is 19.

The square root of 2217421 is about 1489.1007353433. The cubic root of 2217421 is about 130.4015395267.

Subtracting from 2217421 its reverse (1247122), we obtain a cube (970299 = 99³).

The spelling of 2217421 in words is "two million, two hundred seventeen thousand, four hundred twenty-one".