3991523744643 has 4 divisors (see below), whose sum is σ = 5322031659528. Its totient is φ = 2661015829760.

The previous prime is 3991523744641. The next prime is 3991523744701. The reversal of 3991523744643 is 3464473251993.

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 3991523744643 - 2¹ = 3991523744641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3991523744641) 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, 665253957438 + ... + 665253957443.

It is an arithmetic number, because the mean of its divisors is an integer number (1330507914882).

Almost surely, 2^{3991523744643} is an apocalyptic number.

3991523744643 is a deficient number, since it is larger than the sum of its proper divisors (1330507914885).

3991523744643 is a wasteful number, since it uses less digits than its factorization.

3991523744643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1330507914884.

The product of its digits is 58786560, while the sum is 60.

The spelling of 3991523744643 in words is "three trillion, nine hundred ninety-one billion, five hundred twenty-three million, seven hundred forty-four thousand, six hundred forty-three".