684203621 has 2 divisors, whose sum is σ = 684203622. Its totient is φ = 684203620.

The previous prime is 684203599. The next prime is 684203629. The reversal of 684203621 is 126302486.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 644652100 + 39551521 = 25390^2 + 6289^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684203621 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684203629) 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, 342101810 + 342101811.

It is an arithmetic number, because the mean of its divisors is an integer number (342101811).

Almost surely, 2^684203621 is an apocalyptic number.

It is an amenable number.

684203621 is a deficient number, since it is larger than the sum of its proper divisors (1).

684203621 is an equidigital number, since it uses as much as digits as its factorization.

684203621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 684203621 is about 26157.2861933344. The cubic root of 684203621 is about 881.1742335075.

The spelling of 684203621 in words is "six hundred eighty-four million, two hundred three thousand, six hundred twenty-one".