21163600575781 has 2 divisors, whose sum is σ = 21163600575782. Its totient is φ = 21163600575780.

The previous prime is 21163600575749. The next prime is 21163600575841. The reversal of 21163600575781 is 18757500636112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17202668712100 + 3960931863681 = 4147610^2 + 1990209^2 .

It is a cyclic number.

It is not a de Polignac number, because 21163600575781 - 2⁵ = 21163600575749 is a prime.

It is a super-2 number, since 2×21163600575781² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21163600575581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10581800287890 + 10581800287891.

It is an arithmetic number, because the mean of its divisors is an integer number (10581800287891).

Almost surely, 2^{21163600575781} is an apocalyptic number.

It is an amenable number.

21163600575781 is a deficient number, since it is larger than the sum of its proper divisors (1).

21163600575781 is an equidigital number, since it uses as much as digits as its factorization.

21163600575781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2116800, while the sum is 52.

The spelling of 21163600575781 in words is "twenty-one trillion, one hundred sixty-three billion, six hundred million, five hundred seventy-five thousand, seven hundred eighty-one".