28809788561 has 2 divisors, whose sum is σ = 28809788562. Its totient is φ = 28809788560.

The previous prime is 28809788549. The next prime is 28809788587. The reversal of 28809788561 is 16588790882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19287932161 + 9521856400 = 138881^2 + 97580^2 .

It is a cyclic number.

It is not a de Polignac number, because 28809788561 - 2³⁴ = 11629919377 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28809788494 and 28809788503.

It is not a weakly prime, because it can be changed into another prime (28809788261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14404894280 + 14404894281.

It is an arithmetic number, because the mean of its divisors is an integer number (14404894281).

Almost surely, 2^28809788561 is an apocalyptic number.

It is an amenable number.

28809788561 is a deficient number, since it is larger than the sum of its proper divisors (1).

28809788561 is an equidigital number, since it uses as much as digits as its factorization.

28809788561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15482880, while the sum is 62.

The spelling of 28809788561 in words is "twenty-eight billion, eight hundred nine million, seven hundred eighty-eight thousand, five hundred sixty-one".