28378769 has 2 divisors, whose sum is σ = 28378770. Its totient is φ = 28378768.

The previous prime is 28378759. The next prime is 28378781. The reversal of 28378769 is 96787382.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14592400 + 13786369 = 3820^2 + 3713^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28378769 is a prime.

It is a super-2 number, since 2×28378769² = 1610709059910722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (28378709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14189384 + 14189385.

It is an arithmetic number, because the mean of its divisors is an integer number (14189385).

Almost surely, 2^28378769 is an apocalyptic number.

It is an amenable number.

28378769 is a deficient number, since it is larger than the sum of its proper divisors (1).

28378769 is an equidigital number, since it uses as much as digits as its factorization.

28378769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1016064, while the sum is 50.

The square root of 28378769 is about 5327.1727022878. The cubic root of 28378769 is about 305.0220139983.

The spelling of 28378769 in words is "twenty-eight million, three hundred seventy-eight thousand, seven hundred sixty-nine".