• 724 can be written using four 4's:

See also 113.

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724 has 6 divisors (see below), whose sum is σ = 1274. Its totient is φ = 360.

The previous prime is 719. The next prime is 727. The reversal of 724 is 427.

724 = T₁₇ + T₁₈ + ... + T₂₀.

724 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 only one way, i.e., 400 + 324 = 20^2 + 18^2 .

It is a plaindrome in base 14 and base 15.

It is a nialpdrome in base 3 and base 9.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 87 + ... + 94.

It is an amenable number.

724 is a deficient number, since it is larger than the sum of its proper divisors (550).

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

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

The sum of its prime factors is 185 (or 183 counting only the distinct ones).

The product of its digits is 56, while the sum is 13.

The square root of 724 is about 26.9072480941. The cubic root of 724 is about 8.9793766463.

Adding to 724 its sum of digits (13), we get a palindrome (737).

Adding to 724 its product of digits (56), we get a triangular number (780 = T₃₉).

The spelling of 724 in words is "seven hundred twenty-four", and thus it is an aban number and an iban number.