21071712191 has 2 divisors, whose sum is σ = 21071712192. Its totient is φ = 21071712190.

The previous prime is 21071712173. The next prime is 21071712203. The reversal of 21071712191 is 19121717012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21071712191 - 2¹⁴ = 21071695807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21071702191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10535856095 + 10535856096.

It is an arithmetic number, because the mean of its divisors is an integer number (10535856096).

Almost surely, 2^21071712191 is an apocalyptic number.

21071712191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21071712191 is an equidigital number, since it uses as much as digits as its factorization.

21071712191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1764, while the sum is 32.

The spelling of 21071712191 in words is "twenty-one billion, seventy-one million, seven hundred twelve thousand, one hundred ninety-one".