1644545113 has 4 divisors (see below), whose sum is σ = 1647111348. Its totient is φ = 1641978880.

The previous prime is 1644545101. The next prime is 1644545153. The reversal of 1644545113 is 3115454461.

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 587189824 + 1057355289 = 24232^2 + 32517^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1644545113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1644545153) 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, 1282156 + ... + 1283437.

It is an arithmetic number, because the mean of its divisors is an integer number (411777837).

Almost surely, 2^1644545113 is an apocalyptic number.

It is an amenable number.

1644545113 is a deficient number, since it is larger than the sum of its proper divisors (2566235).

1644545113 is an equidigital number, since it uses as much as digits as its factorization.

1644545113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2566234.

The product of its digits is 28800, while the sum is 34.

The square root of 1644545113 is about 40552.9914186364. The cubic root of 1644545113 is about 1180.3621202596.

Adding to 1644545113 its reverse (3115454461), we get a palindrome (4759999574).

The spelling of 1644545113 in words is "one billion, six hundred forty-four million, five hundred forty-five thousand, one hundred thirteen".