28890821779 has 2 divisors, whose sum is σ = 28890821780. Its totient is φ = 28890821778.

The previous prime is 28890821759. The next prime is 28890821789. The reversal of 28890821779 is 97712809882.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28890821779 - 2⁵ = 28890821747 is a prime.

It is not a weakly prime, because it can be changed into another prime (28890821759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14445410889 + 14445410890.

It is an arithmetic number, because the mean of its divisors is an integer number (14445410890).

Almost surely, 2^28890821779 is an apocalyptic number.

28890821779 is a deficient number, since it is larger than the sum of its proper divisors (1).

28890821779 is an equidigital number, since it uses as much as digits as its factorization.

28890821779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8128512, while the sum is 61.

The spelling of 28890821779 in words is "twenty-eight billion, eight hundred ninety million, eight hundred twenty-one thousand, seven hundred seventy-nine".