21355233 has 4 divisors (see below), whose sum is σ = 28473648. Its totient is φ = 14236820.

The previous prime is 21355231. The next prime is 21355241. The reversal of 21355233 is 33255312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21355233 - 2¹ = 21355231 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21355231) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3559203 + ... + 3559208.

It is an arithmetic number, because the mean of its divisors is an integer number (7118412).

Almost surely, 2^21355233 is an apocalyptic number.

It is an amenable number.

21355233 is a deficient number, since it is larger than the sum of its proper divisors (7118415).

21355233 is an equidigital number, since it uses as much as digits as its factorization.

21355233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7118414.

The product of its digits is 2700, while the sum is 24.

The square root of 21355233 is about 4621.1722538767. The cubic root of 21355233 is about 277.4393796648.

The spelling of 21355233 in words is "twenty-one million, three hundred fifty-five thousand, two hundred thirty-three".