3991947386 has 72 divisors (see below), whose sum is σ = 7493668020. Its totient is φ = 1589462784.

The previous prime is 3991947383. The next prime is 3991947389. The reversal of 3991947386 is 6837491993.

It is an interprime number because it is at equal distance from previous prime (3991947383) and next prime (3991947389).

It can be written as a sum of positive squares in 2 ways, for example, as 3991080625 + 866761 = 63175^2 + 931^2 .

It is not an unprimeable number, because it can be changed into a prime (3991947383) 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 35 ways as a sum of consecutive naturals, for example, 1873970 + ... + 1876098.

Almost surely, 2^3991947386 is an apocalyptic number.

3991947386 is a deficient number, since it is larger than the sum of its proper divisors (3501720634).

3991947386 is a wasteful number, since it uses less digits than its factorization.

3991947386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2236 (or 2210 counting only the distinct ones).

The product of its digits is 8817984, while the sum is 59.

The square root of 3991947386 is about 63181.8596275861. The cubic root of 3991947386 is about 1586.3351090177.

The spelling of 3991947386 in words is "three billion, nine hundred ninety-one million, nine hundred forty-seven thousand, three hundred eighty-six".