21678717328 has 20 divisors (see below), whose sum is σ = 42374222028. Its totient is φ = 10743434240.

The previous prime is 21678717311. The next prime is 21678717343. The reversal of 21678717328 is 82371787612.

It can be written as a sum of positive squares in 2 ways, for example, as 8307957904 + 13370759424 = 91148^2 + 115632^2 .

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, 5993413 + ... + 5997028.

Almost surely, 2^21678717328 is an apocalyptic number.

It is an amenable number.

21678717328 is a deficient number, since it is larger than the sum of its proper divisors (20695504700).

21678717328 is a wasteful number, since it uses less digits than its factorization.

21678717328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11990562 (or 11990556 counting only the distinct ones).

The product of its digits is 1580544, while the sum is 52.

The spelling of 21678717328 in words is "twenty-one billion, six hundred seventy-eight million, seven hundred seventeen thousand, three hundred twenty-eight".