28971726555661 has 2 divisors, whose sum is σ = 28971726555662. Its totient is φ = 28971726555660.

The previous prime is 28971726555523. The next prime is 28971726555677. The reversal of 28971726555661 is 16655562717982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15910477574436 + 13061248981225 = 3988794^2 + 3614035^2 .

It is a cyclic number.

It is not a de Polignac number, because 28971726555661 - 2¹¹ = 28971726553613 is a prime.

It is a super-2 number, since 2×28971726555661² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28971726555691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14485863277830 + 14485863277831.

It is an arithmetic number, because the mean of its divisors is an integer number (14485863277831).

Almost surely, 2^{28971726555661} is an apocalyptic number.

It is an amenable number.

28971726555661 is a deficient number, since it is larger than the sum of its proper divisors (1).

28971726555661 is an equidigital number, since it uses as much as digits as its factorization.

28971726555661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 381024000, while the sum is 70.

The spelling of 28971726555661 in words is "twenty-eight trillion, nine hundred seventy-one billion, seven hundred twenty-six million, five hundred fifty-five thousand, six hundred sixty-one".