3999955 has 4 divisors (see below), whose sum is σ = 4799952. Its totient is φ = 3199960.

The previous prime is 3999949. The next prime is 3999971. The reversal of 3999955 is 5599993.

It is a happy number.

3999955 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5599993 = 7 ⋅799999.

It is not a de Polignac number, because 3999955 - 2⁵ = 3999923 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

3999955 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 3999899 and 3999908.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 399991 + ... + 400000.

It is an arithmetic number, because the mean of its divisors is an integer number (1199988).

Almost surely, 2^3999955 is an apocalyptic number.

3999955 is a deficient number, since it is larger than the sum of its proper divisors (799997).

3999955 is an equidigital number, since it uses as much as digits as its factorization.

3999955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 799996.

The product of its digits is 492075, while the sum is 49.

The square root of 3999955 is about 1999.9887499684. The cubic root of 3999955 is about 158.7395099192.

Adding to 3999955 its sum of digits (49), we get a palindrome (4000004).

The spelling of 3999955 in words is "three million, nine hundred ninety-nine thousand, nine hundred fifty-five".