721735 has 16 divisors (see below), whose sum is σ = 1048896. Its totient is φ = 465408.

The previous prime is 721733. The next prime is 721739. The reversal of 721735 is 537127.

It is a cyclic number.

It is not a de Polignac number, because 721735 - 2¹ = 721733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721733) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12 + ... + 1201.

It is an arithmetic number, because the mean of its divisors is an integer number (65556).

2⁷²¹⁷³⁵ is an apocalyptic number.

721735 is a deficient number, since it is larger than the sum of its proper divisors (327161).

721735 is a wasteful number, since it uses less digits than its factorization.

721735 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1242.

The product of its digits is 1470, while the sum is 25.

The square root of 721735 is about 849.5498808192. The cubic root of 721735 is about 89.7000301181.

It can be divided in two parts, 721 and 735, that multiplied together give a triangular number (529935 = T₁₀₂₉).

The spelling of 721735 in words is "seven hundred twenty-one thousand, seven hundred thirty-five".