21288798732521 has 2 divisors, whose sum is σ = 21288798732522. Its totient is φ = 21288798732520.

The previous prime is 21288798732491. The next prime is 21288798732527. The reversal of 21288798732521 is 12523789788212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17933014398121 + 3355784334400 = 4234739^2 + 1831880^2 .

It is a cyclic number.

It is not a de Polignac number, because 21288798732521 - 2¹⁸ = 21288798470377 is a prime.

It is a super-2 number, since 2×21288798732521² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21288798732527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10644399366260 + 10644399366261.

It is an arithmetic number, because the mean of its divisors is an integer number (10644399366261).

Almost surely, 2^{21288798732521} is an apocalyptic number.

It is an amenable number.

21288798732521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21288798732521 is an equidigital number, since it uses as much as digits as its factorization.

21288798732521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54190080, while the sum is 65.

The spelling of 21288798732521 in words is "twenty-one trillion, two hundred eighty-eight billion, seven hundred ninety-eight million, seven hundred thirty-two thousand, five hundred twenty-one".