681673 has 2 divisors, whose sum is σ = 681674. Its totient is φ = 681672.

The previous prime is 681647. The next prime is 681677. The reversal of 681673 is 376186.

681673 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., 644809 + 36864 = 803^2 + 192^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681673 is a prime.

It is not a weakly prime, because it can be changed into another prime (681677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340836 + 340837.

It is an arithmetic number, because the mean of its divisors is an integer number (340837).

2⁶⁸¹⁶⁷³ is an apocalyptic number.

It is an amenable number.

681673 is a deficient number, since it is larger than the sum of its proper divisors (1).

681673 is an equidigital number, since it uses as much as digits as its factorization.

681673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 681673 is about 825.6349072078. The cubic root of 681673 is about 88.0086510090.

It can be divided in two parts, 6816 and 73, that added together give a square (6889 = 83²).

The spelling of 681673 in words is "six hundred eighty-one thousand, six hundred seventy-three".