28720660055569 has 2 divisors, whose sum is σ = 28720660055570. Its totient is φ = 28720660055568.

The previous prime is 28720660055491. The next prime is 28720660055573. The reversal of 28720660055569 is 96555006602782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20970354835600 + 7750305219969 = 4579340^2 + 2783937^2 .

It is a cyclic number.

It is not a de Polignac number, because 28720660055569 - 2⁷ = 28720660055441 is a prime.

It is a super-2 number, since 2×28720660055569² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28720660055599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14360330027784 + 14360330027785.

It is an arithmetic number, because the mean of its divisors is an integer number (14360330027785).

Almost surely, 2^{28720660055569} is an apocalyptic number.

It is an amenable number.

28720660055569 is a deficient number, since it is larger than the sum of its proper divisors (1).

28720660055569 is an equidigital number, since it uses as much as digits as its factorization.

28720660055569 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432000, while the sum is 61.

The spelling of 28720660055569 in words is "twenty-eight trillion, seven hundred twenty billion, six hundred sixty million, fifty-five thousand, five hundred sixty-nine".