684523813 has 2 divisors, whose sum is σ = 684523814. Its totient is φ = 684523812.

The previous prime is 684523789. The next prime is 684523877. The reversal of 684523813 is 318325486.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 529322049 + 155201764 = 23007^2 + 12458^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684523813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684520813) 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, 342261906 + 342261907.

It is an arithmetic number, because the mean of its divisors is an integer number (342261907).

Almost surely, 2^684523813 is an apocalyptic number.

It is an amenable number.

684523813 is a deficient number, since it is larger than the sum of its proper divisors (1).

684523813 is an equidigital number, since it uses as much as digits as its factorization.

684523813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 138240, while the sum is 40.

The square root of 684523813 is about 26163.4059900465. The cubic root of 684523813 is about 881.3116686854.

The spelling of 684523813 in words is "six hundred eighty-four million, five hundred twenty-three thousand, eight hundred thirteen".