728791665 has 16 divisors (see below), whose sum is σ = 1332647808. Its totient is φ = 333161856.

The previous prime is 728791643. The next prime is 728791667. The reversal of 728791665 is 566197827.

It is not a de Polignac number, because 728791665 - 2⁶ = 728791601 is a prime.

It is a super-2 number, since 2×728791665² = 1062274581946944450, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (728791667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3470332 + ... + 3470541.

It is an arithmetic number, because the mean of its divisors is an integer number (83290488).

Almost surely, 2^728791665 is an apocalyptic number.

It is an amenable number.

728791665 is a deficient number, since it is larger than the sum of its proper divisors (603856143).

728791665 is a wasteful number, since it uses less digits than its factorization.

728791665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6940888.

The product of its digits is 1270080, while the sum is 51.

The square root of 728791665 is about 26996.1416687644. The cubic root of 728791665 is about 899.9142572637.

The spelling of 728791665 in words is "seven hundred twenty-eight million, seven hundred ninety-one thousand, six hundred sixty-five".