21777866069 has 2 divisors, whose sum is σ = 21777866070. Its totient is φ = 21777866068.

The previous prime is 21777866057. The next prime is 21777866179. The reversal of 21777866069 is 96066877712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12754765969 + 9023100100 = 112937^2 + 94990^2 .

It is a cyclic number.

It is not a de Polignac number, because 21777866069 - 2⁴ = 21777866053 is a prime.

It is a super-2 number, since 2×21777866069² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21777865999 and 21777866017.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21777865069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10888933034 + 10888933035.

It is an arithmetic number, because the mean of its divisors is an integer number (10888933035).

Almost surely, 2^21777866069 is an apocalyptic number.

It is an amenable number.

21777866069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21777866069 is an equidigital number, since it uses as much as digits as its factorization.

21777866069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10668672, while the sum is 59.

The spelling of 21777866069 in words is "twenty-one billion, seven hundred seventy-seven million, eight hundred sixty-six thousand, sixty-nine".