21426305 has 12 divisors (see below), whose sum is σ = 26051772. Its totient is φ = 16917120.

The previous prime is 21426289. The next prime is 21426329. The reversal of 21426305 is 50362412.

It can be written as a sum of positive squares in 6 ways, for example, as 4129024 + 17297281 = 2032^2 + 4159^2 .

It is not a de Polignac number, because 21426305 - 2⁴ = 21426289 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39335 + ... + 39875.

It is an arithmetic number, because the mean of its divisors is an integer number (2170981).

Almost surely, 2^21426305 is an apocalyptic number.

It is an amenable number.

21426305 is a deficient number, since it is larger than the sum of its proper divisors (4625467).

21426305 is an frugal number, since it uses more digits than its factorization.

21426305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724 (or 635 counting only the distinct ones).

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

The square root of 21426305 is about 4628.8556901247. The cubic root of 21426305 is about 277.7468193350.

Adding to 21426305 its reverse (50362412), we get a palindrome (71788717).

The spelling of 21426305 in words is "twenty-one million, four hundred twenty-six thousand, three hundred five".