21644044612 has 6 divisors (see below), whose sum is σ = 37877078078. Its totient is φ = 10822022304.

The previous prime is 21644044601. The next prime is 21644044613.

21644044612 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 21306073156 + 337971456 = 145966^2 + 18384^2 .

It is not an unprimeable number, because it can be changed into a prime (21644044613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2705505573 + ... + 2705505580.

Almost surely, 2^21644044612 is an apocalyptic number.

It is an amenable number.

21644044612 is a deficient number, since it is larger than the sum of its proper divisors (16233033466).

21644044612 is a wasteful number, since it uses less digits than its factorization.

21644044612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5411011157 (or 5411011155 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 34.

The spelling of 21644044612 in words is "twenty-one billion, six hundred forty-four million, forty-four thousand, six hundred twelve".