729521 has 8 divisors (see below), whose sum is σ = 832104. Its totient is φ = 633600.

The previous prime is 729511. The next prime is 729527. The reversal of 729521 is 125927.

729521 = T₁₄₃ + T₁₄₄ + ... + T₁₉₃.

It can be written as a sum of positive squares in 4 ways, for example, as 25600 + 703921 = 160^2 + 839^2 .

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 729521 - 2⁶ = 729457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (729527) 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, 1430 + ... + 1871.

It is an arithmetic number, because the mean of its divisors is an integer number (104013).

2⁷²⁹⁵²¹ is an apocalyptic number.

It is an amenable number.

729521 is a deficient number, since it is larger than the sum of its proper divisors (102583).

729521 is a wasteful number, since it uses less digits than its factorization.

729521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3331.

The product of its digits is 1260, while the sum is 26.

The square root of 729521 is about 854.1200149862. The cubic root of 729521 is about 90.0214352236.

The spelling of 729521 in words is "seven hundred twenty-nine thousand, five hundred twenty-one".