21244644621 has 12 divisors (see below), whose sum is σ = 30688070400. Its totient is φ = 14162468040.

The previous prime is 21244644611. The next prime is 21244644671. The reversal of 21244644621 is 12644644212.

21244644621 is a `hidden beast` number, since 2 + 1 + 2 + 4 + 4 + 644 + 6 + 2 + 1 = 666.

It is not a de Polignac number, because 21244644621 - 2⁷ = 21244644493 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244644601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 259530 + ... + 331428.

It is an arithmetic number, because the mean of its divisors is an integer number (2557339200).

Almost surely, 2^21244644621 is an apocalyptic number.

It is an amenable number.

21244644621 is a deficient number, since it is larger than the sum of its proper divisors (9443425779).

21244644621 is a wasteful number, since it uses less digits than its factorization.

21244644621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104736 (or 104733 counting only the distinct ones).

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

The spelling of 21244644621 in words is "twenty-one billion, two hundred forty-four million, six hundred forty-four thousand, six hundred twenty-one".