15867221609 has 6 divisors (see below), whose sum is σ = 16855491774. Its totient is φ = 14933855360.

The previous prime is 15867221597. The next prime is 15867221611. The reversal of 15867221609 is 90612276851.

It is a happy number.

15867221609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 2305920400 + 13561301209 = 48020^2 + 116453^2 .

It is not a de Polignac number, because 15867221609 - 2⁴ = 15867221593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15867221809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27451652 + ... + 27452229.

It is an arithmetic number, because the mean of its divisors is an integer number (2809248629).

Almost surely, 2^15867221609 is an apocalyptic number.

It is an amenable number.

15867221609 is a deficient number, since it is larger than the sum of its proper divisors (988270165).

15867221609 is an equidigital number, since it uses as much as digits as its factorization.

15867221609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54903915 (or 54903898 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 47.

The spelling of 15867221609 in words is "fifteen billion, eight hundred sixty-seven million, two hundred twenty-one thousand, six hundred nine".