28021769 has 2 divisors, whose sum is σ = 28021770. Its totient is φ = 28021768.

The previous prime is 28021757. The next prime is 28021771. The reversal of 28021769 is 96712082.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27175369 + 846400 = 5213^2 + 920^2 .

It is a cyclic number.

It is not a de Polignac number, because 28021769 - 2¹⁶ = 27956233 is a prime.

It is a super-2 number, since 2×28021769² = 1570439075778722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 28021771, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (28021709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14010884 + 14010885.

It is an arithmetic number, because the mean of its divisors is an integer number (14010885).

Almost surely, 2^28021769 is an apocalyptic number.

It is an amenable number.

28021769 is a deficient number, since it is larger than the sum of its proper divisors (1).

28021769 is an equidigital number, since it uses as much as digits as its factorization.

28021769 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 28021769 is about 5293.5591996312. The cubic root of 28021769 is about 303.7375714515.

The spelling of 28021769 in words is "twenty-eight million, twenty-one thousand, seven hundred sixty-nine".