21172580771 has 2 divisors, whose sum is σ = 21172580772. Its totient is φ = 21172580770.

The previous prime is 21172580711. The next prime is 21172580789. The reversal of 21172580771 is 17708527112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21172580771 is a prime.

It is not a weakly prime, because it can be changed into another prime (21172580711) 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, 10586290385 + 10586290386.

It is an arithmetic number, because the mean of its divisors is an integer number (10586290386).

Almost surely, 2^21172580771 is an apocalyptic number.

21172580771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21172580771 is an equidigital number, since it uses as much as digits as its factorization.

21172580771 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54880, while the sum is 41.

The spelling of 21172580771 in words is "twenty-one billion, one hundred seventy-two million, five hundred eighty thousand, seven hundred seventy-one".