20540609 has 2 divisors, whose sum is σ = 20540610. Its totient is φ = 20540608.

The previous prime is 20540603. The next prime is 20540629. The reversal of 20540609 is 90604502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18731584 + 1809025 = 4328^2 + 1345^2 .

It is a cyclic number.

It is not a de Polignac number, because 20540609 - 2⁴ = 20540593 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 (20540603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10270304 + 10270305.

It is an arithmetic number, because the mean of its divisors is an integer number (10270305).

Almost surely, 2^20540609 is an apocalyptic number.

It is an amenable number.

20540609 is a deficient number, since it is larger than the sum of its proper divisors (1).

20540609 is an equidigital number, since it uses as much as digits as its factorization.

20540609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20540609 is about 4532.1748642346. The cubic root of 20540609 is about 273.8657813166.

The spelling of 20540609 in words is "twenty million, five hundred forty thousand, six hundred nine".