660038791 has 4 divisors (see below), whose sum is σ = 669335184. Its totient is φ = 650742400.

The previous prime is 660038789. The next prime is 660038803. The reversal of 660038791 is 197830066.

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

It is a cyclic number.

It is not a de Polignac number, because 660038791 - 2¹ = 660038789 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660038591) 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, 4648090 + ... + 4648231.

It is an arithmetic number, because the mean of its divisors is an integer number (167333796).

Almost surely, 2^660038791 is an apocalyptic number.

660038791 is a deficient number, since it is larger than the sum of its proper divisors (9296393).

660038791 is an equidigital number, since it uses as much as digits as its factorization.

660038791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9296392.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 660038791 is about 25691.2201150510. The cubic root of 660038791 is about 870.6758262197.

The spelling of 660038791 in words is "six hundred sixty million, thirty-eight thousand, seven hundred ninety-one".