15981191 has 4 divisors (see below), whose sum is σ = 16008384. Its totient is φ = 15954000.

The previous prime is 15981181. The next prime is 15981193. The reversal of 15981191 is 19118951.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19118951 = 71 ⋅269281.

It is a cyclic number.

It is not a de Polignac number, because 15981191 - 2⁶ = 15981127 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 (15981193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12695 + ... + 13896.

It is an arithmetic number, because the mean of its divisors is an integer number (4002096).

Almost surely, 2^15981191 is an apocalyptic number.

15981191 is a deficient number, since it is larger than the sum of its proper divisors (27193).

15981191 is an equidigital number, since it uses as much as digits as its factorization.

15981191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27192.

The product of its digits is 3240, while the sum is 35.

The square root of 15981191 is about 3997.6481836200. The cubic root of 15981191 is about 251.8854301990.

Subtracting from 15981191 its product of digits (3240), we obtain a palindrome (15977951).

The spelling of 15981191 in words is "fifteen million, nine hundred eighty-one thousand, one hundred ninety-one".