21728666476 has 72 divisors (see below), whose sum is σ = 42781163040. Its totient is φ = 9646560000.

The previous prime is 21728666471. The next prime is 21728666483. The reversal of 21728666476 is 67466682712.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21728666471) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3742776 + ... + 3748576.

It is an arithmetic number, because the mean of its divisors is an integer number (594182820).

Almost surely, 2^21728666476 is an apocalyptic number.

It is an amenable number.

21728666476 is a deficient number, since it is larger than the sum of its proper divisors (21052496564).

21728666476 is a wasteful number, since it uses less digits than its factorization.

21728666476 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6007 (or 5994 counting only the distinct ones).

The product of its digits is 8128512, while the sum is 55.

The spelling of 21728666476 in words is "twenty-one billion, seven hundred twenty-eight million, six hundred sixty-six thousand, four hundred seventy-six".