40278509 has 2 divisors, whose sum is σ = 40278510. Its totient is φ = 40278508.

The previous prime is 40278503. The next prime is 40278527. The reversal of 40278509 is 90587204.

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., 36844900 + 3433609 = 6070^2 + 1853^2 .

It is a cyclic number.

It is not a de Polignac number, because 40278509 - 2⁴ = 40278493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40278503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20139254 + 20139255.

It is an arithmetic number, because the mean of its divisors is an integer number (20139255).

Almost surely, 2^40278509 is an apocalyptic number.

It is an amenable number.

40278509 is a deficient number, since it is larger than the sum of its proper divisors (1).

40278509 is an equidigital number, since it uses as much as digits as its factorization.

40278509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 40278509 is about 6346.5351964674. The cubic root of 40278509 is about 342.7870937167.

The spelling of 40278509 in words is "forty million, two hundred seventy-eight thousand, five hundred nine".