720616891 has 4 divisors (see below), whose sum is σ = 728713800. Its totient is φ = 712519984.

The previous prime is 720616823. The next prime is 720616903. The reversal of 720616891 is 198616027.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720616891 is a prime.

It is a super-3 number, since 3×720616891³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720616811) 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, 4048321 + ... + 4048498.

It is an arithmetic number, because the mean of its divisors is an integer number (182178450).

Almost surely, 2^720616891 is an apocalyptic number.

720616891 is a deficient number, since it is larger than the sum of its proper divisors (8096909).

720616891 is an equidigital number, since it uses as much as digits as its factorization.

720616891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8096908.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 720616891 is about 26844.3083539137. The cubic root of 720616891 is about 896.5368520045.

The spelling of 720616891 in words is "seven hundred twenty million, six hundred sixteen thousand, eight hundred ninety-one".