28561511663021 has 2 divisors, whose sum is σ = 28561511663022. Its totient is φ = 28561511663020.

The previous prime is 28561511662997. The next prime is 28561511663029. The reversal of 28561511663021 is 12036611516582.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27251427684100 + 1310083978921 = 5220290^2 + 1144589^2 .

It is a cyclic number.

It is not a de Polignac number, because 28561511663021 - 2¹⁰ = 28561511661997 is a prime.

It is a super-3 number, since 3×28561511663021³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28561511663029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14280755831510 + 14280755831511.

It is an arithmetic number, because the mean of its divisors is an integer number (14280755831511).

Almost surely, 2^{28561511663021} is an apocalyptic number.

It is an amenable number.

28561511663021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28561511663021 is an equidigital number, since it uses as much as digits as its factorization.

28561511663021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 518400, while the sum is 47.

The spelling of 28561511663021 in words is "twenty-eight trillion, five hundred sixty-one billion, five hundred eleven million, six hundred sixty-three thousand, twenty-one".