723921 has 8 divisors (see below), whose sum is σ = 1053024. Its totient is φ = 438720.

The previous prime is 723917. The next prime is 723923. The reversal of 723921 is 129327.

723921 is nontrivially palindromic in base 5.

723921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 723921 - 2² = 723917 is a prime.

It is a super-2 number, since 2×723921² = 1048123228482, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 723891 and 723900.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 723921.

It is not an unprimeable number, because it can be changed into a prime (723923) 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, 10936 + ... + 11001.

It is an arithmetic number, because the mean of its divisors is an integer number (131628).

2⁷²³⁹²¹ is an apocalyptic number.

It is an amenable number.

723921 is a deficient number, since it is larger than the sum of its proper divisors (329103).

723921 is a wasteful number, since it uses less digits than its factorization.

723921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21951.

The product of its digits is 756, while the sum is 24.

The square root of 723921 is about 850.8354717570. The cubic root of 723921 is about 89.7905003650.

It can be divided in two parts, 7239 and 21, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 723921 in words is "seven hundred twenty-three thousand, nine hundred twenty-one".