3991215 has 8 divisors (see below), whose sum is σ = 6385968. Its totient is φ = 2128640.

The previous prime is 3991199. The next prime is 3991223. The reversal of 3991215 is 5121993.

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

It is not a de Polignac number, because 3991215 - 2⁴ = 3991199 is a prime.

It is a nialpdrome in base 13.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133026 + ... + 133055.

It is an arithmetic number, because the mean of its divisors is an integer number (798246).

Almost surely, 2^3991215 is an apocalyptic number.

3991215 is a deficient number, since it is larger than the sum of its proper divisors (2394753).

3991215 is a wasteful number, since it uses less digits than its factorization.

3991215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266089.

The product of its digits is 2430, while the sum is 30.

The square root of 3991215 is about 1997.8025427955. The cubic root of 3991215 is about 158.6238090314.

The spelling of 3991215 in words is "three million, nine hundred ninety-one thousand, two hundred fifteen".