21221768072 has 16 divisors (see below), whose sum is σ = 40104130560. Its totient is φ = 10527333264.

The previous prime is 21221768047. The next prime is 21221768081. The reversal of 21221768072 is 27086712212.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10442768 + ... + 10444799.

It is an arithmetic number, because the mean of its divisors is an integer number (2506508160).

Almost surely, 2^21221768072 is an apocalyptic number.

It is an amenable number.

21221768072 is a deficient number, since it is larger than the sum of its proper divisors (18882362488).

21221768072 is a wasteful number, since it uses less digits than its factorization.

21221768072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20887700 (or 20887696 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 38.

The spelling of 21221768072 in words is "twenty-one billion, two hundred twenty-one million, seven hundred sixty-eight thousand, seventy-two".