21650178689 has 2 divisors, whose sum is σ = 21650178690. Its totient is φ = 21650178688.

The previous prime is 21650178677. The next prime is 21650178721. The reversal of 21650178689 is 98687105612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20451288064 + 1198890625 = 143008^2 + 34625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21650178689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21650178689.

It is not a weakly prime, because it can be changed into another prime (21650178989) 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 as a sum of consecutive naturals, namely, 10825089344 + 10825089345.

It is an arithmetic number, because the mean of its divisors is an integer number (10825089345).

Almost surely, 2^21650178689 is an apocalyptic number.

It is an amenable number.

21650178689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21650178689 is an equidigital number, since it uses as much as digits as its factorization.

21650178689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1451520, while the sum is 53.

The spelling of 21650178689 in words is "twenty-one billion, six hundred fifty million, one hundred seventy-eight thousand, six hundred eighty-nine".