21051766765069 has 2 divisors, whose sum is σ = 21051766765070. Its totient is φ = 21051766765068.

The previous prime is 21051766765039. The next prime is 21051766765103. The reversal of 21051766765069 is 96056766715012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17505964784169 + 3545801980900 = 4184013^2 + 1883030^2 .

It is a cyclic number.

It is not a de Polignac number, because 21051766765069 - 2¹¹ = 21051766763021 is a prime.

It is a super-2 number, since 2×21051766765069² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21051766764998 and 21051766765016.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21051766765039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525883382534 + 10525883382535.

It is an arithmetic number, because the mean of its divisors is an integer number (10525883382535).

Almost surely, 2^{21051766765069} is an apocalyptic number.

It is an amenable number.

21051766765069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21051766765069 is an equidigital number, since it uses as much as digits as its factorization.

21051766765069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28576800, while the sum is 61.

The spelling of 21051766765069 in words is "twenty-one trillion, fifty-one billion, seven hundred sixty-six million, seven hundred sixty-five thousand, sixty-nine".