21644244612 has 36 divisors (see below), whose sum is σ = 54756397696. Its totient is φ = 7208872560.

The previous prime is 21644244581. The next prime is 21644244613.

21644244612 is a `hidden beast` number, since 2 + 1 + 644 + 2 + 4 + 4 + 6 + 1 + 2 = 666.

21644244612 is nontrivially palindromic in base 10.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21644244613) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 199888 + ... + 288519.

Almost surely, 2^21644244612 is an apocalyptic number.

It is an amenable number.

21644244612 is an abundant number, since it is smaller than the sum of its proper divisors (33112153084).

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

21644244612 is a wasteful number, since it uses less digits than its factorization.

21644244612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489648 (or 489643 counting only the distinct ones).

The product of its digits is 73728, while the sum is 36.

It can be divided in two parts, 21644 and 244612, that added together give a square (266256 = 516²).

The spelling of 21644244612 in words is "twenty-one billion, six hundred forty-four million, two hundred forty-four thousand, six hundred twelve".