21085752988057 has 2 divisors, whose sum is σ = 21085752988058. Its totient is φ = 21085752988056.

The previous prime is 21085752987997. The next prime is 21085752988099. The reversal of 21085752988057 is 75088925758012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15979038869641 + 5106714118416 = 3997379^2 + 2259804^2 .

It is a cyclic number.

It is not a de Polignac number, because 21085752988057 - 2³⁹ = 20535997174169 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21085752987983 and 21085752988001.

It is not a weakly prime, because it can be changed into another prime (21085752988757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10542876494028 + 10542876494029.

It is an arithmetic number, because the mean of its divisors is an integer number (10542876494029).

Almost surely, 2^{21085752988057} is an apocalyptic number.

It is an amenable number.

21085752988057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21085752988057 is an equidigital number, since it uses as much as digits as its factorization.

21085752988057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112896000, while the sum is 67.

The spelling of 21085752988057 in words is "twenty-one trillion, eighty-five billion, seven hundred fifty-two million, nine hundred eighty-eight thousand, fifty-seven".