21646722044 has 24 divisors (see below), whose sum is σ = 39972955680. Its totient is φ = 10236452864.

The previous prime is 21646722011. The next prime is 21646722049. The reversal of 21646722044 is 44022764612.

It is a junction number, because it is equal to n+sod(n) for n = 21646721989 and 21646722007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21646722049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1313669 + ... + 1330044.

It is an arithmetic number, because the mean of its divisors is an integer number (1665539820).

Almost surely, 2^21646722044 is an apocalyptic number.

It is an amenable number.

21646722044 is a deficient number, since it is larger than the sum of its proper divisors (18326233636).

21646722044 is a wasteful number, since it uses less digits than its factorization.

21646722044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2643829 (or 2643827 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 38.

The spelling of 21646722044 in words is "twenty-one billion, six hundred forty-six million, seven hundred twenty-two thousand, forty-four".