21644813223 has 32 divisors (see below), whose sum is σ = 35126784000. Its totient is φ = 13063593600.

The previous prime is 21644813213. The next prime is 21644813233. The reversal of 21644813223 is 32231844612.

21644813223 is a `hidden beast` number, since 2 + 1 + 644 + 8 + 1 + 3 + 2 + 2 + 3 = 666.

It is an interprime number because it is at equal distance from previous prime (21644813213) and next prime (21644813233).

It is not a de Polignac number, because 21644813223 - 2¹³ = 21644805031 is a prime.

It is a super-3 number, since 3×21644813223³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21644813213) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79623 + ... + 222776.

It is an arithmetic number, because the mean of its divisors is an integer number (1097712000).

Almost surely, 2^21644813223 is an apocalyptic number.

21644813223 is a deficient number, since it is larger than the sum of its proper divisors (13481970777).

21644813223 is a wasteful number, since it uses less digits than its factorization.

21644813223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302660 (or 302654 counting only the distinct ones).

The product of its digits is 55296, while the sum is 36.

The spelling of 21644813223 in words is "twenty-one billion, six hundred forty-four million, eight hundred thirteen thousand, two hundred twenty-three".