427217221 has 4 divisors (see below), whose sum is σ = 434220844. Its totient is φ = 420213600.

The previous prime is 427217213. The next prime is 427217233. The reversal of 427217221 is 122712724.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 190826596 + 236390625 = 13814^2 + 15375^2 .

It is a cyclic number.

It is not a de Polignac number, because 427217221 - 2³ = 427217213 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 427217221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (427217251) 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, 3501720 + ... + 3501841.

It is an arithmetic number, because the mean of its divisors is an integer number (108555211).

Almost surely, 2^427217221 is an apocalyptic number.

It is an amenable number.

427217221 is a deficient number, since it is larger than the sum of its proper divisors (7003623).

427217221 is an equidigital number, since it uses as much as digits as its factorization.

427217221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7003622.

The product of its digits is 3136, while the sum is 28.

The square root of 427217221 is about 20669.2336819728. The cubic root of 427217221 is about 753.1524910932.

Adding to 427217221 its reverse (122712724), we get a palindrome (549929945).

The spelling of 427217221 in words is "four hundred twenty-seven million, two hundred seventeen thousand, two hundred twenty-one".