21375065347777 has 2 divisors, whose sum is σ = 21375065347778. Its totient is φ = 21375065347776.

The previous prime is 21375065347759. The next prime is 21375065347799. The reversal of 21375065347777 is 77774356057312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12123272458801 + 9251792888976 = 3481849^2 + 3041676^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21375065347777 is a prime.

It is not a weakly prime, because it can be changed into another prime (21375065347747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10687532673888 + 10687532673889.

It is an arithmetic number, because the mean of its divisors is an integer number (10687532673889).

Almost surely, 2^{21375065347777} is an apocalyptic number.

It is an amenable number.

21375065347777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21375065347777 is an equidigital number, since it uses as much as digits as its factorization.

21375065347777 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181515600, while the sum is 64.

The spelling of 21375065347777 in words is "twenty-one trillion, three hundred seventy-five billion, sixty-five million, three hundred forty-seven thousand, seven hundred seventy-seven".