721115510716836 has 243 divisors, whose sum is σ = 1901878895451171. Its totient is φ = 230370323234688.

The previous prime is 721115510716739. The next prime is 721115510716859. The reversal of 721115510716836 is 638617015511127.

It is a happy number.

The square root of 721115510716836 is 26853594.

It is a perfect power (a square), and thus also a powerful number.

721115510716836 is a `hidden beast` number, since 7 + 2 + 1 + 1 + 1 + 551 + 0 + 7 + 1 + 6 + 83 + 6 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 25429730984100 + 695685779732736 = 5042790^2 + 26375856^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 733586480401 + ... + 733586481383.

Almost surely, 2^{721115510716836} is an apocalyptic number.

721115510716836 is the 26853594-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721115510716836

721115510716836 is an abundant number, since it is smaller than the sum of its proper divisors (1180763384734335).

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

721115510716836 is an equidigital number, since it uses as much as digits as its factorization.

721115510716836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2348 (or 1174 counting only the distinct ones).

The product of its (nonzero) digits is 2116800, while the sum is 54.

The spelling of 721115510716836 in words is "seven hundred twenty-one trillion, one hundred fifteen billion, five hundred ten million, seven hundred sixteen thousand, eight hundred thirty-six".