3991543357 has 4 divisors (see below), whose sum is σ = 4056978556. Its totient is φ = 3926108160.

The previous prime is 3991543333. The next prime is 3991543379. The reversal of 3991543357 is 7533451993.

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

It can be written as a sum of positive squares in 2 ways, for example, as 324756441 + 3666786916 = 18021^2 + 60554^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3991543357 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3991543357.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991543057) 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, 32717508 + ... + 32717629.

It is an arithmetic number, because the mean of its divisors is an integer number (1014244639).

Almost surely, 2^3991543357 is an apocalyptic number.

It is an amenable number.

3991543357 is a deficient number, since it is larger than the sum of its proper divisors (65435199).

3991543357 is an equidigital number, since it uses as much as digits as its factorization.

3991543357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65435198.

The product of its digits is 1530900, while the sum is 49.

The square root of 3991543357 is about 63178.6621969791. The cubic root of 3991543357 is about 1586.2815890228.

The spelling of 3991543357 in words is "three billion, nine hundred ninety-one million, five hundred forty-three thousand, three hundred fifty-seven".