21788627669 has 2 divisors, whose sum is σ = 21788627670. Its totient is φ = 21788627668.

The previous prime is 21788627647. The next prime is 21788627689. The reversal of 21788627669 is 96672688712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18895801444 + 2892826225 = 137462^2 + 53785^2 .

It is a cyclic number.

It is not a de Polignac number, because 21788627669 - 2²⁴ = 21771850453 is a prime.

It is a super-2 number, since 2×21788627669² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 10894313834 + 10894313835.

It is an arithmetic number, because the mean of its divisors is an integer number (10894313835).

Almost surely, 2^21788627669 is an apocalyptic number.

It is an amenable number.

21788627669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21788627669 is an equidigital number, since it uses as much as digits as its factorization.

21788627669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24385536, while the sum is 62.

The spelling of 21788627669 in words is "twenty-one billion, seven hundred eighty-eight million, six hundred twenty-seven thousand, six hundred sixty-nine".