15643609 has 4 divisors (see below), whose sum is σ = 15678900. Its totient is φ = 15608320.

The previous prime is 15643603. The next prime is 15643613. The reversal of 15643609 is 90634651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90634651 = 23 ⋅3940637.

It can be written as a sum of positive squares in 2 ways, for example, as 5626384 + 10017225 = 2372^2 + 3165^2 .

It is a cyclic number.

It is not a de Polignac number, because 15643609 - 2⁵ = 15643577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15643603) 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, 16972 + ... + 17869.

It is an arithmetic number, because the mean of its divisors is an integer number (3919725).

Almost surely, 2^15643609 is an apocalyptic number.

It is an amenable number.

15643609 is a deficient number, since it is larger than the sum of its proper divisors (35291).

15643609 is an equidigital number, since it uses as much as digits as its factorization.

15643609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35290.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 15643609 is about 3955.2002477751. The cubic root of 15643609 is about 250.0992086254.

The spelling of 15643609 in words is "fifteen million, six hundred forty-three thousand, six hundred nine".