21095916697 has 2 divisors, whose sum is σ = 21095916698. Its totient is φ = 21095916696.

The previous prime is 21095916691. The next prime is 21095916701. The reversal of 21095916697 is 79661959012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10628785216 + 10467131481 = 103096^2 + 102309^2 .

It is a cyclic number.

It is not a de Polignac number, because 21095916697 - 2¹¹ = 21095914649 is a prime.

It is not a weakly prime, because it can be changed into another prime (21095916691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10547958348 + 10547958349.

It is an arithmetic number, because the mean of its divisors is an integer number (10547958349).

Almost surely, 2^21095916697 is an apocalyptic number.

It is an amenable number.

21095916697 is a deficient number, since it is larger than the sum of its proper divisors (1).

21095916697 is an equidigital number, since it uses as much as digits as its factorization.

21095916697 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1837080, while the sum is 55.

The spelling of 21095916697 in words is "twenty-one billion, ninety-five million, nine hundred sixteen thousand, six hundred ninety-seven".