15481991 has 8 divisors (see below), whose sum is σ = 18055200. Its totient is φ = 13269984.

The previous prime is 15481981. The next prime is 15481993. The reversal of 15481991 is 19918451.

It is not a de Polignac number, because 15481991 - 2¹⁰ = 15480967 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 (15481993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22226 + ... + 22911.

It is an arithmetic number, because the mean of its divisors is an integer number (2256900).

Almost surely, 2^15481991 is an apocalyptic number.

15481991 is a deficient number, since it is larger than the sum of its proper divisors (2573209).

15481991 is an frugal number, since it uses more digits than its factorization.

15481991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45158 (or 45144 counting only the distinct ones).

The product of its digits is 12960, while the sum is 38.

The square root of 15481991 is about 3934.7161269906. The cubic root of 15481991 is about 249.2349464941.

The spelling of 15481991 in words is "fifteen million, four hundred eighty-one thousand, nine hundred ninety-one".