721878 has 16 divisors (see below), whose sum is σ = 1506816. Its totient is φ = 230120.

The previous prime is 721859. The next prime is 721883. The reversal of 721878 is 878127.

721878 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×721878² = 1042215693768, which contains 22 as substring.

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

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 721878.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2478 + ... + 2753.

It is an arithmetic number, because the mean of its divisors is an integer number (94176).

2⁷²¹⁸⁷⁸ is an apocalyptic number.

721878 is an abundant number, since it is smaller than the sum of its proper divisors (784938).

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

721878 is a wasteful number, since it uses less digits than its factorization.

721878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5259.

The product of its digits is 6272, while the sum is 33.

The square root of 721878 is about 849.6340388661. The cubic root of 721878 is about 89.7059539255.

The spelling of 721878 in words is "seven hundred twenty-one thousand, eight hundred seventy-eight".