21540422 has 8 divisors (see below), whose sum is σ = 32344272. Its totient is φ = 10759000.

The previous prime is 21540383. The next prime is 21540437. The reversal of 21540422 is 22404512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21540394 and 21540403.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2954 + ... + 7197.

It is an arithmetic number, because the mean of its divisors is an integer number (4043034).

Almost surely, 2^21540422 is an apocalyptic number.

21540422 is a deficient number, since it is larger than the sum of its proper divisors (10803850).

21540422 is a wasteful number, since it uses less digits than its factorization.

21540422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11214.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21540422 is about 4641.1660172849. The cubic root of 21540422 is about 278.2390418489.

Adding to 21540422 its reverse (22404512), we get a palindrome (43944934).

The spelling of 21540422 in words is "twenty-one million, five hundred forty thousand, four hundred twenty-two".