40643509 has 2 divisors, whose sum is σ = 40643510. Its totient is φ = 40643508.

The previous prime is 40643503. The next prime is 40643531. The reversal of 40643509 is 90534604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38812900 + 1830609 = 6230^2 + 1353^2 .

It is a cyclic number.

It is not a de Polignac number, because 40643509 - 2⁷ = 40643381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40643503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20321754 + 20321755.

It is an arithmetic number, because the mean of its divisors is an integer number (20321755).

Almost surely, 2^40643509 is an apocalyptic number.

It is an amenable number.

40643509 is a deficient number, since it is larger than the sum of its proper divisors (1).

40643509 is an equidigital number, since it uses as much as digits as its factorization.

40643509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 40643509 is about 6375.2261920657. The cubic root of 40643509 is about 343.8194163283.

The spelling of 40643509 in words is "forty million, six hundred forty-three thousand, five hundred nine".