15991125 has 16 divisors (see below), whose sum is σ = 26609856. Its totient is φ = 8528400.

The previous prime is 15991121. The next prime is 15991159. The reversal of 15991125 is 52119951.

It is a happy number.

It is not a de Polignac number, because 15991125 - 2² = 15991121 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15991121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20947 + ... + 21696.

It is an arithmetic number, because the mean of its divisors is an integer number (1663116).

Almost surely, 2^15991125 is an apocalyptic number.

15991125 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

15991125 is a deficient number, since it is larger than the sum of its proper divisors (10618731).

15991125 is an equidigital number, since it uses as much as digits as its factorization.

15991125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42661 (or 42651 counting only the distinct ones).

The product of its digits is 4050, while the sum is 33.

The square root of 15991125 is about 3998.8904711182. The cubic root of 15991125 is about 251.9376105314.

The spelling of 15991125 in words is "fifteen million, nine hundred ninety-one thousand, one hundred twenty-five".