729781 has 8 divisors (see below), whose sum is σ = 797720. Its totient is φ = 663552.

The previous prime is 729779. The next prime is 729787. The reversal of 729781 is 187927.

729781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 22500 + 707281 = 150^2 + 841^2 .

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

It is a 7-Lehmer number, since φ(729781) divides (729781-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 729781 - 2¹ = 729779 is a prime.

It is a super-2 number, since 2×729781² = 1065160615922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (729787) 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, 565 + ... + 1333.

It is an arithmetic number, because the mean of its divisors is an integer number (99715).

2⁷²⁹⁷⁸¹ is an apocalyptic number.

It is an amenable number.

729781 is a deficient number, since it is larger than the sum of its proper divisors (67939).

729781 is a wasteful number, since it uses less digits than its factorization.

729781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 855.

The product of its digits is 7056, while the sum is 34.

The square root of 729781 is about 854.2722048621. The cubic root of 729781 is about 90.0321284470.

The spelling of 729781 in words is "seven hundred twenty-nine thousand, seven hundred eighty-one".