720697681 has 16 divisors (see below), whose sum is σ = 796481280. Its totient is φ = 646663680.

The previous prime is 720697669. The next prime is 720697687. The reversal of 720697681 is 186796027.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 720697681 - 2²¹ = 718600529 is a prime.

It is a super-2 number, since 2×720697681² = 1038810294797555522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720697687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 542440 + ... + 543766.

It is an arithmetic number, because the mean of its divisors is an integer number (49780080).

Almost surely, 2^720697681 is an apocalyptic number.

It is an amenable number.

720697681 is a deficient number, since it is larger than the sum of its proper divisors (75783599).

720697681 is a wasteful number, since it uses less digits than its factorization.

720697681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1944.

The product of its (nonzero) digits is 254016, while the sum is 46.

The square root of 720697681 is about 26845.8130999975. The cubic root of 720697681 is about 896.5703550149.

The spelling of 720697681 in words is "seven hundred twenty million, six hundred ninety-seven thousand, six hundred eighty-one".