1681609723 has 8 divisors (see below), whose sum is σ = 1780890192. Its totient is φ = 1582369536.

The previous prime is 1681609691. The next prime is 1681609739. The reversal of 1681609723 is 3279061861.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1681609723 - 2⁵ = 1681609691 is a prime.

It is a super-2 number, since 2×1681609723² = 5655622520976273458, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1681609723.

It is not an unprimeable number, because it can be changed into a prime (1681609123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139336 + ... + 150922.

It is an arithmetic number, because the mean of its divisors is an integer number (222611274).

Almost surely, 2^1681609723 is an apocalyptic number.

1681609723 is a deficient number, since it is larger than the sum of its proper divisors (99280469).

1681609723 is a wasteful number, since it uses less digits than its factorization.

1681609723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20141.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 1681609723 is about 41007.4349722096. The cubic root of 1681609723 is about 1189.1639545829.

The spelling of 1681609723 in words is "one billion, six hundred eighty-one million, six hundred nine thousand, seven hundred twenty-three".