729665 has 4 divisors (see below), whose sum is σ = 875604. Its totient is φ = 583728.

The previous prime is 729661. The next prime is 729671. The reversal of 729665 is 566927.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 579121 + 150544 = 761^2 + 388^2 .

It is a cyclic number.

It is not a de Polignac number, because 729665 - 2² = 729661 is a prime.

It is a super-2 number, since 2×729665² = 1064822024450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (729661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72962 + ... + 72971.

It is an arithmetic number, because the mean of its divisors is an integer number (218901).

2⁷²⁹⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

729665 is a deficient number, since it is larger than the sum of its proper divisors (145939).

729665 is a wasteful number, since it uses less digits than its factorization.

729665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145938.

The product of its digits is 22680, while the sum is 35.

The square root of 729665 is about 854.2043081137. The cubic root of 729665 is about 90.0273579381.

The spelling of 729665 in words is "seven hundred twenty-nine thousand, six hundred sixty-five".