721342736 has 20 divisors (see below), whose sum is σ = 1402583964. Its totient is φ = 359385600.

The previous prime is 721342709. The next prime is 721342753. The reversal of 721342736 is 637243127.

721342736 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 634032400 + 87310336 = 25180^2 + 9344^2 .

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 721342696 and 721342705.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75725 + ... + 84716.

Almost surely, 2^721342736 is an apocalyptic number.

It is an amenable number.

721342736 is a deficient number, since it is larger than the sum of its proper divisors (681241228).

721342736 is a wasteful number, since it uses less digits than its factorization.

721342736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160730 (or 160724 counting only the distinct ones).

The product of its digits is 42336, while the sum is 35.

The square root of 721342736 is about 26857.8244837515. The cubic root of 721342736 is about 896.8377647513.

The spelling of 721342736 in words is "seven hundred twenty-one million, three hundred forty-two thousand, seven hundred thirty-six".