721224842 has 16 divisors (see below), whose sum is σ = 1166152680. Its totient is φ = 332559552.

The previous prime is 721224841. The next prime is 721224851. The reversal of 721224842 is 248422127.

It can be written as a sum of positive squares in 4 ways, for example, as 512162161 + 209062681 = 22631^2 + 14459^2 .

It is a junction number, because it is equal to n+sod(n) for n = 721224799 and 721224808.

It is not an unprimeable number, because it can be changed into a prime (721224841) 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, 16328 + ... + 41340.

Almost surely, 2^721224842 is an apocalyptic number.

721224842 is a deficient number, since it is larger than the sum of its proper divisors (444927838).

721224842 is a wasteful number, since it uses less digits than its factorization.

721224842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26137.

The product of its digits is 14336, while the sum is 32.

The square root of 721224842 is about 26855.6296146637. The cubic root of 721224842 is about 896.7889033032.

Adding to 721224842 its reverse (248422127), we get a palindrome (969646969).

The spelling of 721224842 in words is "seven hundred twenty-one million, two hundred twenty-four thousand, eight hundred forty-two".