15981265 has 4 divisors (see below), whose sum is σ = 19177524. Its totient is φ = 12785008.

The previous prime is 15981263. The next prime is 15981281. The reversal of 15981265 is 56218951.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11350161 + 4631104 = 3369^2 + 2152^2 .

It is a cyclic number.

It is not a de Polignac number, because 15981265 - 2¹ = 15981263 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15981263) 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, 1598122 + ... + 1598131.

It is an arithmetic number, because the mean of its divisors is an integer number (4794381).

Almost surely, 2^15981265 is an apocalyptic number.

It is an amenable number.

15981265 is a deficient number, since it is larger than the sum of its proper divisors (3196259).

15981265 is an equidigital number, since it uses as much as digits as its factorization.

15981265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3196258.

The product of its digits is 21600, while the sum is 37.

The square root of 15981265 is about 3997.6574390510. The cubic root of 15981265 is about 251.8858189788.

The spelling of 15981265 in words is "fifteen million, nine hundred eighty-one thousand, two hundred sixty-five".