3991955 has 16 divisors (see below), whose sum is σ = 5267808. Its totient is φ = 2880000.

The previous prime is 3991943. The next prime is 3991961. The reversal of 3991955 is 5591993.

It is not a de Polignac number, because 3991955 - 2⁶ = 3991891 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9755 + ... + 10155.

It is an arithmetic number, because the mean of its divisors is an integer number (329238).

Almost surely, 2^3991955 is an apocalyptic number.

3991955 is a deficient number, since it is larger than the sum of its proper divisors (1275853).

3991955 is a wasteful number, since it uses less digits than its factorization.

3991955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598.

The product of its digits is 54675, while the sum is 41.

The square root of 3991955 is about 1997.9877377001. The cubic root of 3991955 is about 158.6336117577.

The spelling of 3991955 in words is "three million, nine hundred ninety-one thousand, nine hundred fifty-five".