3991209811 has 8 divisors (see below), whose sum is σ = 4049478320. Its totient is φ = 3933038592.

The previous prime is 3991209791. The next prime is 3991209841. The reversal of 3991209811 is 1189021993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3991209811 - 2⁷ = 3991209683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3991209841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60460 + ... + 107878.

It is an arithmetic number, because the mean of its divisors is an integer number (506184790).

Almost surely, 2^3991209811 is an apocalyptic number.

3991209811 is a deficient number, since it is larger than the sum of its proper divisors (58268509).

3991209811 is a wasteful number, since it uses less digits than its factorization.

3991209811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48645.

The product of its (nonzero) digits is 34992, while the sum is 43.

The square root of 3991209811 is about 63176.0224373140. The cubic root of 3991209811 is about 1586.2374028881.

The spelling of 3991209811 in words is "three billion, nine hundred ninety-one million, two hundred nine thousand, eight hundred eleven".