681729 has 8 divisors (see below), whose sum is σ = 917472. Its totient is φ = 450240.

The previous prime is 681727. The next prime is 681731. The reversal of 681729 is 927186.

It is an interprime number because it is at equal distance from previous prime (681727) and next prime (681731).

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

It is not a de Polignac number, because 681729 - 2¹ = 681727 is a prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 681729.

It is not an unprimeable number, because it can be changed into a prime (681727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 667 + ... + 1344.

It is an arithmetic number, because the mean of its divisors is an integer number (114684).

2⁶⁸¹⁷²⁹ is an apocalyptic number.

It is an amenable number.

681729 is a deficient number, since it is larger than the sum of its proper divisors (235743).

681729 is a wasteful number, since it uses less digits than its factorization.

681729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2127.

The product of its digits is 6048, while the sum is 33.

The square root of 681729 is about 825.6688198061. The cubic root of 681729 is about 88.0110609375.

The spelling of 681729 in words is "six hundred eighty-one thousand, seven hundred twenty-nine".