21304445636 has 24 divisors (see below), whose sum is σ = 38582750976. Its totient is φ = 10285198560.

The previous prime is 21304445579. The next prime is 21304445699. The reversal of 21304445636 is 63654440312.

It is a self number, because there is not a number n which added to its sum of digits gives 21304445636.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 530036 + ... + 568811.

It is an arithmetic number, because the mean of its divisors is an integer number (1607614624).

Almost surely, 2^21304445636 is an apocalyptic number.

It is an amenable number.

21304445636 is a deficient number, since it is larger than the sum of its proper divisors (17278305340).

21304445636 is a wasteful number, since it uses less digits than its factorization.

21304445636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1099019 (or 1099017 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 38.

Adding to 21304445636 its reverse (63654440312), we get a palindrome (84958885948).

The spelling of 21304445636 in words is "twenty-one billion, three hundred four million, four hundred forty-five thousand, six hundred thirty-six".