21695312077871 has 2 divisors, whose sum is σ = 21695312077872. Its totient is φ = 21695312077870.

The previous prime is 21695312077861. The next prime is 21695312077883. The reversal of 21695312077871 is 17877021359612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21695312077871 - 2¹⁰ = 21695312076847 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21695312077871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21695312077861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10847656038935 + 10847656038936.

It is an arithmetic number, because the mean of its divisors is an integer number (10847656038936).

Almost surely, 2^{21695312077871} is an apocalyptic number.

21695312077871 is a deficient number, since it is larger than the sum of its proper divisors (1).

21695312077871 is an equidigital number, since it uses as much as digits as its factorization.

21695312077871 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8890560, while the sum is 59.

The spelling of 21695312077871 in words is "twenty-one trillion, six hundred ninety-five billion, three hundred twelve million, seventy-seven thousand, eight hundred seventy-one".