21540041423 has 2 divisors, whose sum is σ = 21540041424. Its totient is φ = 21540041422.

The previous prime is 21540041387. The next prime is 21540041441. The reversal of 21540041423 is 32414004512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21540041423 - 2³² = 17245074127 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21540041392 and 21540041401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21540041473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770020711 + 10770020712.

It is an arithmetic number, because the mean of its divisors is an integer number (10770020712).

Almost surely, 2^21540041423 is an apocalyptic number.

21540041423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21540041423 is an equidigital number, since it uses as much as digits as its factorization.

21540041423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21540041423 its reverse (32414004512), we get a palindrome (53954045935).

The spelling of 21540041423 in words is "twenty-one billion, five hundred forty million, forty-one thousand, four hundred twenty-three".