21444778688 has 28 divisors (see below), whose sum is σ = 42559132560. Its totient is φ = 10721217792.

The previous prime is 21444778687. The next prime is 21444778711. The reversal of 21444778688 is 88687744412.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21444778687) 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, 1150370 + ... + 1168862.

It is an arithmetic number, because the mean of its divisors is an integer number (1519969020).

Almost surely, 2^21444778688 is an apocalyptic number.

It is an amenable number.

21444778688 is a deficient number, since it is larger than the sum of its proper divisors (21114353872).

21444778688 is a wasteful number, since it uses less digits than its factorization.

21444778688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36624 (or 36614 counting only the distinct ones).

The product of its digits is 19267584, while the sum is 59.

The spelling of 21444778688 in words is "twenty-one billion, four hundred forty-four million, seven hundred seventy-eight thousand, six hundred eighty-eight".