1681723 has 2 divisors, whose sum is σ = 1681724. Its totient is φ = 1681722.

The previous prime is 1681721. The next prime is 1681787. The reversal of 1681723 is 3271861.

It is a weak prime.

It is an emirp because it is prime and its reverse (3271861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1681723 - 2¹ = 1681721 is a prime.

Together with 1681721, it forms a pair of twin primes.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 1681691 and 1681700.

It is not a weakly prime, because it can be changed into another prime (1681721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840861 + 840862.

It is an arithmetic number, because the mean of its divisors is an integer number (840862).

2^1681723 is an apocalyptic number.

1681723 is a deficient number, since it is larger than the sum of its proper divisors (1).

1681723 is an equidigital number, since it uses as much as digits as its factorization.

1681723 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 28.

The square root of 1681723 is about 1296.8126310304. The cubic root of 1681723 is about 118.9190655566.

It can be divided in two parts, 168 and 1723, that added together give a triangular number (1891 = T₆₁).

The spelling of 1681723 in words is "one million, six hundred eighty-one thousand, seven hundred twenty-three".