21664464445 has 8 divisors (see below), whose sum is σ = 27997154136. Its totient is φ = 15998373696.

The previous prime is 21664464443. The next prime is 21664464473. The reversal of 21664464445 is 54446446612.

It can be written as a sum of positive squares in 4 ways, for example, as 30173049 + 21634291396 = 5493^2 + 147086^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21664464445 - 2¹ = 21664464443 is a prime.

It is a super-3 number, since 3×21664464445³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21664464395 and 21664464404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21664464443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166649662 + ... + 166649791.

It is an arithmetic number, because the mean of its divisors is an integer number (3499644267).

Almost surely, 2^21664464445 is an apocalyptic number.

It is an amenable number.

21664464445 is a deficient number, since it is larger than the sum of its proper divisors (6332689691).

21664464445 is a wasteful number, since it uses less digits than its factorization.

21664464445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333299471.

The product of its digits is 2211840, while the sum is 46.

It can be divided in two parts, 21 and 664464445, that added together give a palindrome (664464466).

The spelling of 21664464445 in words is "twenty-one billion, six hundred sixty-four million, four hundred sixty-four thousand, four hundred forty-five".