3991225 has 12 divisors (see below), whose sum is σ = 5656384. Its totient is φ = 2736720.

The previous prime is 3991223. The next prime is 3991237. The reversal of 3991225 is 5221993.

It is not a de Polignac number, because 3991225 - 2¹ = 3991223 is a prime.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

3991225 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (3991223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11229 + ... + 11578.

Almost surely, 2^3991225 is an apocalyptic number.

3991225 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

3991225 is a deficient number, since it is larger than the sum of its proper divisors (1665159).

3991225 is a wasteful number, since it uses less digits than its factorization.

3991225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22824 (or 22819 counting only the distinct ones).

The product of its digits is 4860, while the sum is 31.

The square root of 3991225 is about 1997.8050455437. The cubic root of 3991225 is about 158.6239415087.

The spelling of 3991225 in words is "three million, nine hundred ninety-one thousand, two hundred twenty-five".