634421 has 2 divisors, whose sum is σ = 634422. Its totient is φ = 634420.

The previous prime is 634397. The next prime is 634441. The reversal of 634421 is 124436.

It is a happy number.

It is an a-pointer prime, because the next prime (634441) can be obtained adding 634421 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 504100 + 130321 = 710^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 634421 - 2¹⁸ = 372277 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p₅₁₆₇₁ and since 634421 and 51671 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 634393 and 634402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (634441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317210 + 317211.

It is an arithmetic number, because the mean of its divisors is an integer number (317211).

2⁶³⁴⁴²¹ is an apocalyptic number.

It is an amenable number.

634421 is a deficient number, since it is larger than the sum of its proper divisors (1).

634421 is an equidigital number, since it uses as much as digits as its factorization.

634421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 20.

The square root of 634421 is about 796.5054927620. The cubic root of 634421 is about 85.9262482900.

Adding to 634421 its reverse (124436), we get a palindrome (758857).

The spelling of 634421 in words is "six hundred thirty-four thousand, four hundred twenty-one".