721278 has 48 divisors (see below), whose sum is σ = 1737360. Its totient is φ = 221616.

The previous prime is 721267. The next prime is 721283. The reversal of 721278 is 872127.

721278 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is an unprimeable number.

721278 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19476 + ... + 19512.

It is an arithmetic number, because the mean of its divisors is an integer number (36195).

2⁷²¹²⁷⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721278, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (868680).

721278 is an abundant number, since it is smaller than the sum of its proper divisors (1016082).

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

721278 is a wasteful number, since it uses less digits than its factorization.

721278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86 (or 61 counting only the distinct ones).

The product of its digits is 1568, while the sum is 27.

The square root of 721278 is about 849.2808722678. The cubic root of 721278 is about 89.6810935422.

It can be divided in two parts, 721 and 278, that added together give a palindrome (999).

The spelling of 721278 in words is "seven hundred twenty-one thousand, two hundred seventy-eight".