21055835 has 4 divisors (see below), whose sum is σ = 25267008. Its totient is φ = 16844664.

The previous prime is 21055829. The next prime is 21055847. The reversal of 21055835 is 53855012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21055835 - 2⁸ = 21055579 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21055798 and 21055807.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2105579 + ... + 2105588.

It is an arithmetic number, because the mean of its divisors is an integer number (6316752).

Almost surely, 2^21055835 is an apocalyptic number.

21055835 is a deficient number, since it is larger than the sum of its proper divisors (4211173).

21055835 is an equidigital number, since it uses as much as digits as its factorization.

21055835 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4211172.

The product of its (nonzero) digits is 6000, while the sum is 29.

The square root of 21055835 is about 4588.6637488489. The cubic root of 21055835 is about 276.1367163804.

The spelling of 21055835 in words is "twenty-one million, fifty-five thousand, eight hundred thirty-five".