21540027 has 4 divisors (see below), whose sum is σ = 28720040. Its totient is φ = 14360016.

The previous prime is 21540023. The next prime is 21540049. The reversal of 21540027 is 72004512.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21540027 - 2² = 21540023 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21539985 and 21540012.

It is not an unprimeable number, because it can be changed into a prime (21540023) 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 in 3 ways as a sum of consecutive naturals, for example, 3590002 + ... + 3590007.

It is an arithmetic number, because the mean of its divisors is an integer number (7180010).

Almost surely, 2^21540027 is an apocalyptic number.

21540027 is a deficient number, since it is larger than the sum of its proper divisors (7180013).

21540027 is an equidigital number, since it uses as much as digits as its factorization.

21540027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7180012.

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21540027 is about 4641.1234631283. The cubic root of 21540027 is about 278.2373410915.

Adding to 21540027 its reverse (72004512), we get a palindrome (93544539).

The spelling of 21540027 in words is "twenty-one million, five hundred forty thousand, twenty-seven".