3991615 has 8 divisors (see below), whose sum is σ = 5042160. Its totient is φ = 3025152.

The previous prime is 3991613. The next prime is 3991619. The reversal of 3991615 is 5161993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3991615 - 2¹ = 3991613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20914 + ... + 21103.

It is an arithmetic number, because the mean of its divisors is an integer number (630270).

Almost surely, 2^3991615 is an apocalyptic number.

3991615 is a deficient number, since it is larger than the sum of its proper divisors (1050545).

3991615 is a wasteful number, since it uses less digits than its factorization.

3991615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42041.

The product of its digits is 7290, while the sum is 34.

The square root of 3991615 is about 1997.9026502810. The cubic root of 3991615 is about 158.6291079528.

The spelling of 3991615 in words is "three million, nine hundred ninety-one thousand, six hundred fifteen".