646041421 has 2 divisors, whose sum is σ = 646041422. Its totient is φ = 646041420.

The previous prime is 646041419. The next prime is 646041449. The reversal of 646041421 is 124140646.

646041421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (646041449) can be obtained adding 646041421 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 645668100 + 373321 = 25410^2 + 611^2 .

It is a cyclic number.

It is not a de Polignac number, because 646041421 - 2¹ = 646041419 is a prime.

Together with 646041419, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 646041421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646041491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323020710 + 323020711.

It is an arithmetic number, because the mean of its divisors is an integer number (323020711).

Almost surely, 2^646041421 is an apocalyptic number.

It is an amenable number.

646041421 is a deficient number, since it is larger than the sum of its proper divisors (1).

646041421 is an equidigital number, since it uses as much as digits as its factorization.

646041421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 646041421 is about 25417.3448849403. The cubic root of 646041421 is about 864.4770229086.

The spelling of 646041421 in words is "six hundred forty-six million, forty-one thousand, four hundred twenty-one".