21235305 has 64 divisors (see below), whose sum is σ = 42835968. Its totient is φ = 8743680.

The previous prime is 21235297. The next prime is 21235343. The reversal of 21235305 is 50353212.

It is not a de Polignac number, because 21235305 - 2³ = 21235297 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 63990 + ... + 64320.

It is an arithmetic number, because the mean of its divisors is an integer number (669312).

Almost surely, 2^21235305 is an apocalyptic number.

It is an amenable number.

21235305 is an abundant number, since it is smaller than the sum of its proper divisors (21600663).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21235305 is a wasteful number, since it uses less digits than its factorization.

21235305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406.

The product of its (nonzero) digits is 900, while the sum is 21.

The square root of 21235305 is about 4608.1780564557. The cubic root of 21235305 is about 276.9190508377.

Adding to 21235305 its reverse (50353212), we get a palindrome (71588517).

The spelling of 21235305 in words is "twenty-one million, two hundred thirty-five thousand, three hundred five".