421138217 has 2 divisors, whose sum is σ = 421138218. Its totient is φ = 421138216.

The previous prime is 421138199. The next prime is 421138253. The reversal of 421138217 is 712831124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 420414016 + 724201 = 20504^2 + 851^2 .

It is a cyclic number.

It is not a de Polignac number, because 421138217 - 2¹⁰ = 421137193 is a prime.

It is a Chen prime.

It is equal to p_22401848 and since 421138217 and 22401848 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 421138217.

It is not a weakly prime, because it can be changed into another prime (421138117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210569108 + 210569109.

It is an arithmetic number, because the mean of its divisors is an integer number (210569109).

Almost surely, 2^421138217 is an apocalyptic number.

It is an amenable number.

421138217 is a deficient number, since it is larger than the sum of its proper divisors (1).

421138217 is an equidigital number, since it uses as much as digits as its factorization.

421138217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 29.

The square root of 421138217 is about 20521.6523944832. The cubic root of 421138217 is about 749.5631334314.

The spelling of 421138217 in words is "four hundred twenty-one million, one hundred thirty-eight thousand, two hundred seventeen".