21723355244 has 24 divisors (see below), whose sum is σ = 38906886480. Its totient is φ = 10607192064.

The previous prime is 21723355243. The next prime is 21723355249. The reversal of 21723355244 is 44255332712.

It is a junction number, because it is equal to n+sod(n) for n = 21723355198 and 21723355207.

It is not an unprimeable number, because it can be changed into a prime (21723355243) 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, 1885052 + ... + 1896540.

It is an arithmetic number, because the mean of its divisors is an integer number (1621120270).

Almost surely, 2^21723355244 is an apocalyptic number.

It is an amenable number.

21723355244 is a deficient number, since it is larger than the sum of its proper divisors (17183531236).

21723355244 is a wasteful number, since it uses less digits than its factorization.

21723355244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22529 (or 22527 counting only the distinct ones).

The product of its digits is 201600, while the sum is 38.

Adding to 21723355244 its reverse (44255332712), we get a palindrome (65978687956).

The spelling of 21723355244 in words is "twenty-one billion, seven hundred twenty-three million, three hundred fifty-five thousand, two hundred forty-four".