20040509 has 2 divisors, whose sum is σ = 20040510. Its totient is φ = 20040508.

The previous prime is 20040499. The next prime is 20040523. The reversal of 20040509 is 90504002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20025625 + 14884 = 4475^2 + 122^2 .

It is a cyclic number.

It is not a de Polignac number, because 20040509 - 2⁸ = 20040253 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20040409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10020254 + 10020255.

It is an arithmetic number, because the mean of its divisors is an integer number (10020255).

Almost surely, 2^20040509 is an apocalyptic number.

It is an amenable number.

20040509 is a deficient number, since it is larger than the sum of its proper divisors (1).

20040509 is an equidigital number, since it uses as much as digits as its factorization.

20040509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 20040509 is about 4476.6627078662. The cubic root of 20040509 is about 271.6249019733.

The spelling of 20040509 in words is "twenty million, forty thousand, five hundred nine".