3991049186 has 4 divisors (see below), whose sum is σ = 5986573782. Its totient is φ = 1995524592.

The previous prime is 3991049177. The next prime is 3991049197. The reversal of 3991049186 is 6819401993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6819401993 = 673 ⋅10132841.

It can be written as a sum of positive squares in only one way, i.e., 2942520025 + 1048529161 = 54245^2 + 32381^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 997762295 + ... + 997762298.

Almost surely, 2^3991049186 is an apocalyptic number.

3991049186 is a deficient number, since it is larger than the sum of its proper divisors (1995524596).

3991049186 is a wasteful number, since it uses less digits than its factorization.

3991049186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1995524595.

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 3991049186 is about 63174.7511748167. The cubic root of 3991049186 is about 1586.2161233920.

The spelling of 3991049186 in words is "three billion, nine hundred ninety-one million, forty-nine thousand, one hundred eighty-six".