21605342 has 8 divisors (see below), whose sum is σ = 35354232. Its totient is φ = 9820600.

The previous prime is 21605329. The next prime is 21605369. The reversal of 21605342 is 24350612.

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

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 491009 + ... + 491052.

It is an arithmetic number, because the mean of its divisors is an integer number (4419279).

Almost surely, 2^21605342 is an apocalyptic number.

21605342 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21605342 is a deficient number, since it is larger than the sum of its proper divisors (13748890).

21605342 is a wasteful number, since it uses less digits than its factorization.

21605342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 982074.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21605342 is about 4648.1546876153. The cubic root of 21605342 is about 278.5182867980.

Adding to 21605342 its reverse (24350612), we get a palindrome (45955954).

The spelling of 21605342 in words is "twenty-one million, six hundred five thousand, three hundred forty-two".