21273605 has 8 divisors (see below), whose sum is σ = 26122272. Its totient is φ = 16622928.

The previous prime is 21273601. The next prime is 21273611. The reversal of 21273605 is 50637212.

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 21273605 - 2² = 21273601 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21273601) 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, 49259 + ... + 49688.

It is an arithmetic number, because the mean of its divisors is an integer number (3265284).

Almost surely, 2^21273605 is an apocalyptic number.

It is an amenable number.

21273605 is a deficient number, since it is larger than the sum of its proper divisors (4848667).

21273605 is an equidigital number, since it uses as much as digits as its factorization.

21273605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98995.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 21273605 is about 4612.3318397531. The cubic root of 21273605 is about 277.0854345982.

The spelling of 21273605 in words is "twenty-one million, two hundred seventy-three thousand, six hundred five".