15945220609 has 4 divisors (see below), whose sum is σ = 15946959060. Its totient is φ = 15943482160.

The previous prime is 15945220583. The next prime is 15945220631. The reversal of 15945220609 is 90602254951.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90602254951 = 13 ⋅6969404227.

It can be written as a sum of positive squares in 2 ways, for example, as 15599260609 + 345960000 = 124897^2 + 18600^2 .

It is a cyclic number.

It is not a de Polignac number, because 15945220609 - 2¹³ = 15945212417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15945220639) 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, 855394 + ... + 873835.

It is an arithmetic number, because the mean of its divisors is an integer number (3986739765).

Almost surely, 2^15945220609 is an apocalyptic number.

It is an amenable number.

15945220609 is a deficient number, since it is larger than the sum of its proper divisors (1738451).

15945220609 is an equidigital number, since it uses as much as digits as its factorization.

15945220609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1738450.

The product of its (nonzero) digits is 194400, while the sum is 43.

The spelling of 15945220609 in words is "fifteen billion, nine hundred forty-five million, two hundred twenty thousand, six hundred nine".