3999993 has 4 divisors (see below), whose sum is σ = 5333328. Its totient is φ = 2666660.

The previous prime is 3999971. The next prime is 4000037.

3999993 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 3999993 - 2⁶ = 3999929 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (3999923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 666663 + ... + 666668.

It is an arithmetic number, because the mean of its divisors is an integer number (1333332).

Almost surely, 2^3999993 is an apocalyptic number.

It is an amenable number.

3999993 is a deficient number, since it is larger than the sum of its proper divisors (1333335).

3999993 is a wasteful number, since it uses less digits than its factorization.

3999993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333334.

The product of its digits is 531441, while the sum is 51.

The square root of 3999993 is about 1999.9982499992. The cubic root of 3999993 is about 158.7400125984.

The spelling of 3999993 in words is "three million, nine hundred ninety-nine thousand, nine hundred ninety-three".