3991994 has 16 divisors (see below), whose sum is σ = 6279936. Its totient is φ = 1902780.

The previous prime is 3991993. The next prime is 3991997. The reversal of 3991994 is 4991993.

Its product of digits (78732) is a multiple of the sum of its prime factors (162).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991993) 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, 59549 + ... + 59615.

It is an arithmetic number, because the mean of its divisors is an integer number (392496).

Almost surely, 2^3991994 is an apocalyptic number.

3991994 is a deficient number, since it is larger than the sum of its proper divisors (2287942).

3991994 is an frugal number, since it uses more digits than its factorization.

3991994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 100 counting only the distinct ones).

The product of its digits is 78732, while the sum is 44.

The square root of 3991994 is about 1997.9974974959. The cubic root of 3991994 is about 158.6341283543.

Subtracting 3991994 from its reverse (4991993), we obtain a palindrome (999999).

The spelling of 3991994 in words is "three million, nine hundred ninety-one thousand, nine hundred ninety-four".