21012235 has 4 divisors (see below), whose sum is σ = 25214688. Its totient is φ = 16809784.

The previous prime is 21012227. The next prime is 21012239. The reversal of 21012235 is 53221012.

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 21012235 - 2³ = 21012227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012239) by changing a digit.

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, 2101219 + ... + 2101228.

It is an arithmetic number, because the mean of its divisors is an integer number (6303672).

Almost surely, 2^21012235 is an apocalyptic number.

21012235 is a deficient number, since it is larger than the sum of its proper divisors (4202453).

21012235 is an equidigital number, since it uses as much as digits as its factorization.

21012235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4202452.

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

The square root of 21012235 is about 4583.9104485145. The cubic root of 21012235 is about 275.9459872951.

Adding to 21012235 its reverse (53221012), we get a palindrome (74233247).

The spelling of 21012235 in words is "twenty-one million, twelve thousand, two hundred thirty-five".