684259421 has 2 divisors, whose sum is σ = 684259422. Its totient is φ = 684259420.

The previous prime is 684259393. The next prime is 684259427. The reversal of 684259421 is 124952486.

684259421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 683822500 + 436921 = 26150^2 + 661^2 .

It is a cyclic number.

It is not a de Polignac number, because 684259421 - 2⁶ = 684259357 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684259427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342129710 + 342129711.

It is an arithmetic number, because the mean of its divisors is an integer number (342129711).

Almost surely, 2^684259421 is an apocalyptic number.

It is an amenable number.

684259421 is a deficient number, since it is larger than the sum of its proper divisors (1).

684259421 is an equidigital number, since it uses as much as digits as its factorization.

684259421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 138240, while the sum is 41.

The square root of 684259421 is about 26158.3527960000. The cubic root of 684259421 is about 881.1981874807.

The spelling of 684259421 in words is "six hundred eighty-four million, two hundred fifty-nine thousand, four hundred twenty-one".