21401305 has 8 divisors (see below), whose sum is σ = 25743744. Its totient is φ = 17079600.

The previous prime is 21401299. The next prime is 21401321. The reversal of 21401305 is 50310412.

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

It is not a de Polignac number, because 21401305 - 2⁹ = 21400793 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2811 + ... + 7120.

It is an arithmetic number, because the mean of its divisors is an integer number (3217968).

Almost surely, 2^21401305 is an apocalyptic number.

It is an amenable number.

21401305 is a deficient number, since it is larger than the sum of its proper divisors (4342439).

21401305 is an equidigital number, since it uses as much as digits as its factorization.

21401305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10367.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21401305 is about 4626.1544505129. The cubic root of 21401305 is about 277.6387532166.

Adding to 21401305 its reverse (50310412), we get a palindrome (71711717).

The spelling of 21401305 in words is "twenty-one million, four hundred one thousand, three hundred five".