21811328578 has 32 divisors (see below), whose sum is σ = 37099339200. Its totient is φ = 9534044736.

The previous prime is 21811328569. The next prime is 21811328621. The reversal of 21811328578 is 87582311812.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2895525 + ... + 2903047.

It is an arithmetic number, because the mean of its divisors is an integer number (1159354350).

Almost surely, 2^21811328578 is an apocalyptic number.

21811328578 is a deficient number, since it is larger than the sum of its proper divisors (15288010622).

21811328578 is a wasteful number, since it uses less digits than its factorization.

21811328578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13426.

The product of its digits is 215040, while the sum is 46.

The spelling of 21811328578 in words is "twenty-one billion, eight hundred eleven million, three hundred twenty-eight thousand, five hundred seventy-eight".