28659309126721 has 81 divisors (see below), whose sum is σ = 36565634895003. Its totient is φ = 22386797072640.

The previous prime is 28659309126709. The next prime is 28659309126733. The reversal of 28659309126721 is 12762190395682.

The square root of 28659309126721 is 5353439.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (28659309126709) and next prime (28659309126733).

It can be written as a sum of positive squares in 13 ways, for example, as 24769483841025 + 3889825285696 = 4976895^2 + 1972264^2 .

It is not a de Polignac number, because 28659309126721 - 2⁵ = 28659309126689 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28659309126721.

It is not an unprimeable number, because it can be changed into a prime (28659309126751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 43357502131 + ... + 43357502791.

Almost surely, 2^{28659309126721} is an apocalyptic number.

28659309126721 is the 5353439-th square number.

28659309126721 is the 2676720-th centered octagonal number.

It is an amenable number.

28659309126721 is a deficient number, since it is larger than the sum of its proper divisors (7906325768282).

28659309126721 is an frugal number, since it uses more digits than its factorization.

28659309126721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540 (or 770 counting only the distinct ones).

The product of its (nonzero) digits is 19595520, while the sum is 61.

The spelling of 28659309126721 in words is "twenty-eight trillion, six hundred fifty-nine billion, three hundred nine million, one hundred twenty-six thousand, seven hundred twenty-one".