21442505 has 8 divisors (see below), whose sum is σ = 29406912. Its totient is φ = 14703408.

The previous prime is 21442501. The next prime is 21442543. The reversal of 21442505 is 50524412.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21442505 - 2² = 21442501 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21442501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 306287 + ... + 306356.

It is an arithmetic number, because the mean of its divisors is an integer number (3675864).

Almost surely, 2^21442505 is an apocalyptic number.

It is an amenable number.

21442505 is a deficient number, since it is larger than the sum of its proper divisors (7964407).

21442505 is an equidigital number, since it uses as much as digits as its factorization.

21442505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612655.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 21442505 is about 4630.6052520162. The cubic root of 21442505 is about 277.8168013027.

Adding to 21442505 its reverse (50524412), we get a palindrome (71966917).

The spelling of 21442505 in words is "twenty-one million, four hundred forty-two thousand, five hundred five".