21766565011 has 2 divisors, whose sum is σ = 21766565012. Its totient is φ = 21766565010.

The previous prime is 21766564999. The next prime is 21766565047. The reversal of 21766565011 is 11056566712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21766565011 - 2²¹ = 21764467859 is a prime.

It is not a weakly prime, because it can be changed into another prime (21766565081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10883282505 + 10883282506.

It is an arithmetic number, because the mean of its divisors is an integer number (10883282506).

Almost surely, 2^21766565011 is an apocalyptic number.

21766565011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21766565011 is an equidigital number, since it uses as much as digits as its factorization.

21766565011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 75600, while the sum is 40.

The spelling of 21766565011 in words is "twenty-one billion, seven hundred sixty-six million, five hundred sixty-five thousand, eleven".