40278409 has 2 divisors, whose sum is σ = 40278410. Its totient is φ = 40278408.

The previous prime is 40278367. The next prime is 40278421. The reversal of 40278409 is 90487204.

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., 25532809 + 14745600 = 5053^2 + 3840^2 .

It is a cyclic number.

It is not a de Polignac number, because 40278409 - 2⁷ = 40278281 is a prime.

It is not a weakly prime, because it can be changed into another prime (40278449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20139204 + 20139205.

It is an arithmetic number, because the mean of its divisors is an integer number (20139205).

Almost surely, 2^40278409 is an apocalyptic number.

It is an amenable number.

40278409 is a deficient number, since it is larger than the sum of its proper divisors (1).

40278409 is an equidigital number, since it uses as much as digits as its factorization.

40278409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 40278409 is about 6346.5273181481. The cubic root of 40278409 is about 342.7868100357.

The spelling of 40278409 in words is "forty million, two hundred seventy-eight thousand, four hundred nine".