40028509 has 2 divisors, whose sum is σ = 40028510. Its totient is φ = 40028508.

The previous prime is 40028507. The next prime is 40028519. The reversal of 40028509 is 90582004.

It is a happy number.

40028509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35940025 + 4088484 = 5995^2 + 2022^2 .

It is a cyclic number.

It is not a de Polignac number, because 40028509 - 2¹ = 40028507 is a prime.

Together with 40028507, it forms a pair of twin primes.

It is equal to p_2435275 and since 40028509 and 2435275 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40028501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20014254 + 20014255.

It is an arithmetic number, because the mean of its divisors is an integer number (20014255).

Almost surely, 2^40028509 is an apocalyptic number.

It is an amenable number.

40028509 is a deficient number, since it is larger than the sum of its proper divisors (1).

40028509 is an equidigital number, since it uses as much as digits as its factorization.

40028509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 40028509 is about 6326.8087532341. The cubic root of 40028509 is about 342.0764195472.

The spelling of 40028509 in words is "forty million, twenty-eight thousand, five hundred nine".