40917809 has 2 divisors, whose sum is σ = 40917810. Its totient is φ = 40917808.

The previous prime is 40917791. The next prime is 40917913. The reversal of 40917809 is 90871904.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40043584 + 874225 = 6328^2 + 935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40917809 is a prime.

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 (40917509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20458904 + 20458905.

It is an arithmetic number, because the mean of its divisors is an integer number (20458905).

Almost surely, 2^40917809 is an apocalyptic number.

It is an amenable number.

40917809 is a deficient number, since it is larger than the sum of its proper divisors (1).

40917809 is an equidigital number, since it uses as much as digits as its factorization.

40917809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 40917809 is about 6396.7029788790. The cubic root of 40917809 is about 344.5911532935.

The spelling of 40917809 in words is "forty million, nine hundred seventeen thousand, eight hundred nine".