3991538524065 has 16 divisors (see below), whose sum is σ = 6386497023168. Its totient is φ = 2128808751296.

The previous prime is 3991538524063. The next prime is 3991538524159. The reversal of 3991538524065 is 5604258351993.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 3991538524065 - 2¹ = 3991538524063 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3991538524063) 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, 2526454 + ... + 3790256.

It is an arithmetic number, because the mean of its divisors is an integer number (399156063948).

Almost surely, 2^{3991538524065} is an apocalyptic number.

It is an amenable number.

3991538524065 is a deficient number, since it is larger than the sum of its proper divisors (2394958499103).

3991538524065 is a wasteful number, since it uses less digits than its factorization.

3991538524065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1474368.

The product of its (nonzero) digits is 34992000, while the sum is 60.

The spelling of 3991538524065 in words is "three trillion, nine hundred ninety-one billion, five hundred thirty-eight million, five hundred twenty-four thousand, sixty-five".