421605817 has 2 divisors, whose sum is σ = 421605818. Its totient is φ = 421605816.

The previous prime is 421605791. The next prime is 421605823. The reversal of 421605817 is 718506124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 378847296 + 42758521 = 19464^2 + 6539^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421605817 is a prime.

It is not a weakly prime, because it can be changed into another prime (421605517) 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, 210802908 + 210802909.

It is an arithmetic number, because the mean of its divisors is an integer number (210802909).

Almost surely, 2^421605817 is an apocalyptic number.

It is an amenable number.

421605817 is a deficient number, since it is larger than the sum of its proper divisors (1).

421605817 is an equidigital number, since it uses as much as digits as its factorization.

421605817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 421605817 is about 20533.0420785621. The cubic root of 421605817 is about 749.8404502090.

The spelling of 421605817 in words is "four hundred twenty-one million, six hundred five thousand, eight hundred seventeen".