21225135616513 has 2 divisors, whose sum is σ = 21225135616514. Its totient is φ = 21225135616512.

The previous prime is 21225135616507. The next prime is 21225135616577. The reversal of 21225135616513 is 31561653152212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21150506665024 + 74628951489 = 4598968^2 + 273183^2 .

It is a cyclic number.

It is not a de Polignac number, because 21225135616513 - 2⁹ = 21225135616001 is a prime.

It is a super-3 number, since 3×21225135616513³ (a number of 41 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21225135616513.

It is not a weakly prime, because it can be changed into another prime (21225435616513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612567808256 + 10612567808257.

It is an arithmetic number, because the mean of its divisors is an integer number (10612567808257).

Almost surely, 2^{21225135616513} is an apocalyptic number.

It is an amenable number.

21225135616513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21225135616513 is an equidigital number, since it uses as much as digits as its factorization.

21225135616513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 324000, while the sum is 43.

Adding to 21225135616513 its reverse (31561653152212), we get a palindrome (52786788768725).

The spelling of 21225135616513 in words is "twenty-one trillion, two hundred twenty-five billion, one hundred thirty-five million, six hundred sixteen thousand, five hundred thirteen".