12015991 has 8 divisors (see below), whose sum is σ = 13701744. Its totient is φ = 10439040.

The previous prime is 12015977. The next prime is 12016013. The reversal of 12015991 is 19951021.

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 12015991 - 2⁷ = 12015863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12015931) 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, 26965 + ... + 27406.

It is an arithmetic number, because the mean of its divisors is an integer number (1712718).

Almost surely, 2^12015991 is an apocalyptic number.

12015991 is a deficient number, since it is larger than the sum of its proper divisors (1685753).

12015991 is a wasteful number, since it uses less digits than its factorization.

12015991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54401.

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 12015991 is about 3466.4089487537. The cubic root of 12015991 is about 229.0444985131.

The spelling of 12015991 in words is "twelve million, fifteen thousand, nine hundred ninety-one".