21540042463 has 2 divisors, whose sum is σ = 21540042464. Its totient is φ = 21540042462.

The previous prime is 21540042439. The next prime is 21540042533. The reversal of 21540042463 is 36424004512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21540042463 - 2⁵ = 21540042431 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21540042413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770021231 + 10770021232.

It is an arithmetic number, because the mean of its divisors is an integer number (10770021232).

Almost surely, 2^21540042463 is an apocalyptic number.

21540042463 is a deficient number, since it is larger than the sum of its proper divisors (1).

21540042463 is an equidigital number, since it uses as much as digits as its factorization.

21540042463 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23040, while the sum is 31.

Adding to 21540042463 its reverse (36424004512), we get a palindrome (57964046975).

The spelling of 21540042463 in words is "twenty-one billion, five hundred forty million, forty-two thousand, four hundred sixty-three".