28131544608521 has 2 divisors, whose sum is σ = 28131544608522. Its totient is φ = 28131544608520.

The previous prime is 28131544608397. The next prime is 28131544608533. The reversal of 28131544608521 is 12580644513182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28122190817296 + 9353791225 = 5303036^2 + 96715^2 .

It is a cyclic number.

It is not a de Polignac number, because 28131544608521 - 2¹⁸ = 28131544346377 is a prime.

It is a super-2 number, since 2×28131544608521² (a number of 28 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28131544608521.

It is not a weakly prime, because it can be changed into another prime (28131544608571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14065772304260 + 14065772304261.

It is an arithmetic number, because the mean of its divisors is an integer number (14065772304261).

Almost surely, 2^{28131544608521} is an apocalyptic number.

It is an amenable number.

28131544608521 is a deficient number, since it is larger than the sum of its proper divisors (1).

28131544608521 is an equidigital number, since it uses as much as digits as its factorization.

28131544608521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1843200, while the sum is 50.

The spelling of 28131544608521 in words is "twenty-eight trillion, one hundred thirty-one billion, five hundred forty-four million, six hundred eight thousand, five hundred twenty-one".