21738847828 has 12 divisors (see below), whose sum is σ = 38564120980. Its totient is φ = 10720527552.

The previous prime is 21738847771. The next prime is 21738847829. The reversal of 21738847828 is 82874883712.

It can be written as a sum of positive squares in 2 ways, for example, as 6593115204 + 15145732624 = 81198^2 + 123068^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738847829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37223763 + ... + 37224346.

Almost surely, 2^21738847828 is an apocalyptic number.

It is an amenable number.

21738847828 is a deficient number, since it is larger than the sum of its proper divisors (16825273152).

21738847828 is a wasteful number, since it uses less digits than its factorization.

21738847828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74448186 (or 74448184 counting only the distinct ones).

The product of its digits is 9633792, while the sum is 58.

The spelling of 21738847828 in words is "twenty-one billion, seven hundred thirty-eight million, eight hundred forty-seven thousand, eight hundred twenty-eight".