720461813681 has 4 divisors (see below), whose sum is σ = 720463543332. Its totient is φ = 720460084032.

The previous prime is 720461813671. The next prime is 720461813723. The reversal of 720461813681 is 186318164027.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186318164027 = 277 ⋅672628751.

It can be written as a sum of positive squares in 2 ways, for example, as 310338126400 + 410123687281 = 557080^2 + 640409^2 .

It is a cyclic number.

It is not a de Polignac number, because 720461813681 - 2³⁸ = 445583906737 is a prime.

It is a super-2 number, since 2×720461813681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720461813671) 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, 183845 + ... + 1214381.

It is an arithmetic number, because the mean of its divisors is an integer number (180115885833).

Almost surely, 2^720461813681 is an apocalyptic number.

It is an amenable number.

720461813681 is a deficient number, since it is larger than the sum of its proper divisors (1729651).

720461813681 is a wasteful number, since it uses less digits than its factorization.

720461813681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1729650.

The product of its (nonzero) digits is 387072, while the sum is 47.

The spelling of 720461813681 in words is "seven hundred twenty billion, four hundred sixty-one million, eight hundred thirteen thousand, six hundred eighty-one".