28217779 has 2 divisors, whose sum is σ = 28217780. Its totient is φ = 28217778.

The previous prime is 28217741. The next prime is 28217789. The reversal of 28217779 is 97771282.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28217779 - 2¹¹ = 28215731 is a prime.

It is not a weakly prime, because it can be changed into another prime (28217729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14108889 + 14108890.

It is an arithmetic number, because the mean of its divisors is an integer number (14108890).

Almost surely, 2^28217779 is an apocalyptic number.

28217779 is a deficient number, since it is larger than the sum of its proper divisors (1).

28217779 is an equidigital number, since it uses as much as digits as its factorization.

28217779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 98784, while the sum is 43.

The square root of 28217779 is about 5312.0409448723. The cubic root of 28217779 is about 304.4441331102. Note that the first 3 decimals are identical.

The spelling of 28217779 in words is "twenty-eight million, two hundred seventeen thousand, seven hundred seventy-nine".