3991979539 has 4 divisors (see below), whose sum is σ = 3992862024. Its totient is φ = 3991097056.

The previous prime is 3991979533. The next prime is 3991979561. The reversal of 3991979539 is 9359791993.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3991979539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3991979533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 434422 + ... + 443515.

It is an arithmetic number, because the mean of its divisors is an integer number (998215506).

Almost surely, 2^3991979539 is an apocalyptic number.

3991979539 is a deficient number, since it is larger than the sum of its proper divisors (882485).

3991979539 is an equidigital number, since it uses as much as digits as its factorization.

3991979539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 882484.

The product of its digits is 18600435, while the sum is 64.

The square root of 3991979539 is about 63182.1140751083. The cubic root of 3991979539 is about 1586.3393680331.

The spelling of 3991979539 in words is "three billion, nine hundred ninety-one million, nine hundred seventy-nine thousand, five hundred thirty-nine".