21788627689 has 2 divisors, whose sum is σ = 21788627690. Its totient is φ = 21788627688.

The previous prime is 21788627669. The next prime is 21788627713. The reversal of 21788627689 is 98672688712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16969491289 + 4819136400 = 130267^2 + 69420^2 .

It is a cyclic number.

It is not a de Polignac number, because 21788627689 - 2¹⁷ = 21788496617 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21788627689.

It is not a weakly prime, because it can be changed into another prime (21788627639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10894313844 + 10894313845.

It is an arithmetic number, because the mean of its divisors is an integer number (10894313845).

Almost surely, 2^21788627689 is an apocalyptic number.

It is an amenable number.

21788627689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21788627689 is an equidigital number, since it uses as much as digits as its factorization.

21788627689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32514048, while the sum is 64.

The spelling of 21788627689 in words is "twenty-one billion, seven hundred eighty-eight million, six hundred twenty-seven thousand, six hundred eighty-nine".