3999966 has 16 divisors (see below), whose sum is σ = 8025600. Its totient is φ = 1329048.

The previous prime is 3999949. The next prime is 3999971. The reversal of 3999966 is 6699993.

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1395 + ... + 3153.

It is an arithmetic number, because the mean of its divisors is an integer number (501600).

Almost surely, 2^3999966 is an apocalyptic number.

3999966 is an abundant number, since it is smaller than the sum of its proper divisors (4025634).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3999966 is a wasteful number, since it uses less digits than its factorization.

3999966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2143.

The product of its digits is 708588, while the sum is 51.

The square root of 3999966 is about 1999.9914999819. The cubic root of 3999966 is about 158.7396554319.

The spelling of 3999966 in words is "three million, nine hundred ninety-nine thousand, nine hundred sixty-six".