21008565328 has 20 divisors (see below), whose sum is σ = 40737253140. Its totient is φ = 10495725824.

The previous prime is 21008565311. The next prime is 21008565329. The reversal of 21008565328 is 82356580012.

It can be written as a sum of positive squares in 2 ways, for example, as 16587379264 + 4421186064 = 128792^2 + 66492^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21008565329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 514525 + ... + 553852.

It is an arithmetic number, because the mean of its divisors is an integer number (2036862657).

Almost surely, 2^21008565328 is an apocalyptic number.

It is an amenable number.

21008565328 is a deficient number, since it is larger than the sum of its proper divisors (19728687812).

21008565328 is a wasteful number, since it uses less digits than its factorization.

21008565328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1069614 (or 1069608 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 40.

The spelling of 21008565328 in words is "twenty-one billion, eight million, five hundred sixty-five thousand, three hundred twenty-eight".