21540045523 has 2 divisors, whose sum is σ = 21540045524. Its totient is φ = 21540045522.

The previous prime is 21540045463. The next prime is 21540045547. The reversal of 21540045523 is 32554004512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21540045523 - 2⁹ = 21540045011 is a prime.

It is a super-2 number, since 2×21540045523² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21540045323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770022761 + 10770022762.

It is an arithmetic number, because the mean of its divisors is an integer number (10770022762).

Almost surely, 2^21540045523 is an apocalyptic number.

21540045523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21540045523 is an equidigital number, since it uses as much as digits as its factorization.

21540045523 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24000, while the sum is 31.

The spelling of 21540045523 in words is "twenty-one billion, five hundred forty million, forty-five thousand, five hundred twenty-three".