1644541644 has 48 divisors (see below), whose sum is σ = 3887170560. Its totient is φ = 541073280.

The previous prime is 1644541621. The next prime is 1644541649. The reversal of 1644541644 is 4461454461.

It is not an unprimeable number, because it can be changed into a prime (1644541649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 878029 + ... + 879899.

It is an arithmetic number, because the mean of its divisors is an integer number (80982720).

Almost surely, 2^1644541644 is an apocalyptic number.

It is an amenable number.

1644541644 is an abundant number, since it is smaller than the sum of its proper divisors (2242628916).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1644541644 is a wasteful number, since it uses less digits than its factorization.

1644541644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2790 (or 2788 counting only the distinct ones).

The product of its digits is 184320, while the sum is 39.

The square root of 1644541644 is about 40552.9486474165. The cubic root of 1644541644 is about 1180.3612903079.

The spelling of 1644541644 in words is "one billion, six hundred forty-four million, five hundred forty-one thousand, six hundred forty-four".