729121 has 4 divisors (see below), whose sum is σ = 742932. Its totient is φ = 715312.

The previous prime is 729073. The next prime is 729139. The reversal of 729121 is 121927.

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 239121 + 490000 = 489^2 + 700^2 .

It is a cyclic number.

It is not a de Polignac number, because 729121 - 2⁷ = 728993 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a junction number, because it is equal to n+sod(n) for n = 729092 and 729101.

It is not an unprimeable number, because it can be changed into a prime (729191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6826 + ... + 6931.

It is an arithmetic number, because the mean of its divisors is an integer number (185733).

2⁷²⁹¹²¹ is an apocalyptic number.

It is an amenable number.

729121 is a deficient number, since it is larger than the sum of its proper divisors (13811).

729121 is a wasteful number, since it uses less digits than its factorization.

729121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13810.

The product of its digits is 252, while the sum is 22.

The square root of 729121 is about 853.8858237493. The cubic root of 729121 is about 90.0049791484.

It can be divided in two parts, 729 and 121, that multiplied together give a square (88209 = 297²).

The spelling of 729121 in words is "seven hundred twenty-nine thousand, one hundred twenty-one".