684173681 has 2 divisors, whose sum is σ = 684173682. Its totient is φ = 684173680.

The previous prime is 684173671. The next prime is 684173719. The reversal of 684173681 is 186371486.

684173681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 564490081 + 119683600 = 23759^2 + 10940^2 .

It is a cyclic number.

It is not a de Polignac number, because 684173681 - 2¹⁸ = 683911537 is a prime.

It is a super-2 number, since 2×684173681² = 936187251546179522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (684173671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342086840 + 342086841.

It is an arithmetic number, because the mean of its divisors is an integer number (342086841).

Almost surely, 2^684173681 is an apocalyptic number.

It is an amenable number.

684173681 is a deficient number, since it is larger than the sum of its proper divisors (1).

684173681 is an equidigital number, since it uses as much as digits as its factorization.

684173681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 44.

The square root of 684173681 is about 26156.7138799965. The cubic root of 684173681 is about 881.1613802474.

The spelling of 684173681 in words is "six hundred eighty-four million, one hundred seventy-three thousand, six hundred eighty-one".