3999905 has 32 divisors (see below), whose sum is σ = 6048000. Its totient is φ = 2472192.

The previous prime is 3999901. The next prime is 3999917. The reversal of 3999905 is 5099993.

It is a cyclic number.

It is not a de Polignac number, because 3999905 - 2² = 3999901 is a prime.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3999901) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26771 + ... + 26919.

It is an arithmetic number, because the mean of its divisors is an integer number (189000).

Almost surely, 2^3999905 is an apocalyptic number.

3999905 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

3999905 is a deficient number, since it is larger than the sum of its proper divisors (2048095).

3999905 is a wasteful number, since it uses less digits than its factorization.

3999905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233.

The product of its (nonzero) digits is 98415, while the sum is 44.

The square root of 3999905 is about 1999.9762498590. The cubic root of 3999905 is about 158.7388484944.

The spelling of 3999905 in words is "three million, nine hundred ninety-nine thousand, nine hundred five".