21540044334533 has 2 divisors, whose sum is σ = 21540044334534. Its totient is φ = 21540044334532.

The previous prime is 21540044334527. The next prime is 21540044334553. The reversal of 21540044334533 is 33543344004512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17166454270564 + 4373590063969 = 4143242^2 + 2091313^2 .

It is a cyclic number.

It is not a de Polignac number, because 21540044334533 - 2⁴ = 21540044334517 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21540044334553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770022167266 + 10770022167267.

It is an arithmetic number, because the mean of its divisors is an integer number (10770022167267).

Almost surely, 2^{21540044334533} is an apocalyptic number.

It is an amenable number.

21540044334533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21540044334533 is an equidigital number, since it uses as much as digits as its factorization.

21540044334533 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1036800, while the sum is 41.

The spelling of 21540044334533 in words is "twenty-one trillion, five hundred forty billion, forty-four million, three hundred thirty-four thousand, five hundred thirty-three".