721368 has 48 divisors (see below), whose sum is σ = 2007720. Its totient is φ = 233856.

The previous prime is 721363. The next prime is 721379. The reversal of 721368 is 863127.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

Its product of digits (2016) is a multiple of the sum of its prime factors (288).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721368.

It is not an unprimeable number, because it can be changed into a prime (721363) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2980 + ... + 3212.

2⁷²¹³⁶⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1003860).

721368 is an abundant number, since it is smaller than the sum of its proper divisors (1286352).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721368 is a wasteful number, since it uses less digits than its factorization.

721368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 281 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 721368 is about 849.3338566194. Note that the first 3 decimals coincide. The cubic root of 721368 is about 89.6848234783.

It can be divided in two parts, 721 and 368, that added together give a square (1089 = 33²).

The spelling of 721368 in words is "seven hundred twenty-one thousand, three hundred sixty-eight".