20540491 has 2 divisors, whose sum is σ = 20540492. Its totient is φ = 20540490.

The previous prime is 20540483. The next prime is 20540503. The reversal of 20540491 is 19404502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20540491 - 2³ = 20540483 is a prime.

It is not a weakly prime, because it can be changed into another prime (20540431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10270245 + 10270246.

It is an arithmetic number, because the mean of its divisors is an integer number (10270246).

Almost surely, 2^20540491 is an apocalyptic number.

20540491 is a deficient number, since it is larger than the sum of its proper divisors (1).

20540491 is an equidigital number, since it uses as much as digits as its factorization.

20540491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 20540491 is about 4532.1618461833. The cubic root of 20540491 is about 273.8652568884.

Adding to 20540491 its reverse (19404502), we get a palindrome (39944993).

The spelling of 20540491 in words is "twenty million, five hundred forty thousand, four hundred ninety-one".