721145828 has 12 divisors (see below), whose sum is σ = 1359082620. Its totient is φ = 332836512.

The previous prime is 721145827. The next prime is 721145837. The reversal of 721145828 is 828541127.

It can be written as a sum of positive squares in 2 ways, for example, as 91738084 + 629407744 = 9578^2 + 25088^2 .

It is a junction number, because it is equal to n+sod(n) for n = 721145791 and 721145800.

It is not an unprimeable number, because it can be changed into a prime (721145827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6934043 + ... + 6934146.

It is an arithmetic number, because the mean of its divisors is an integer number (113256885).

Almost surely, 2^721145828 is an apocalyptic number.

It is an amenable number.

721145828 is a deficient number, since it is larger than the sum of its proper divisors (637936792).

721145828 is a wasteful number, since it uses less digits than its factorization.

721145828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13868206 (or 13868204 counting only the distinct ones).

The product of its digits is 35840, while the sum is 38.

The square root of 721145828 is about 26854.1584861637. The cubic root of 721145828 is about 896.7561527830.

The spelling of 721145828 in words is "seven hundred twenty-one million, one hundred forty-five thousand, eight hundred twenty-eight".