21032213 has 8 divisors (see below), whose sum is σ = 22521240.
Its totient is φ = 19571200.
The previous prime is 21032201. The next prime is 21032237. The reversal of 21032213 is 31223012.
It is a happy number.
It can be written as a sum of positive squares in 4 ways, for example, as 5650129 + 15382084 = 2377^2 + 3922^2
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is not a de Polignac number, because 21032213 - 24 = 21032197 is a prime.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21032273) 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 7 ways as a sum of consecutive naturals, for example, 5438 + ... + 8463.
It is an arithmetic number, because the mean of its divisors is an integer number (2815155).
Almost surely, 221032213 is an apocalyptic number.
It is an amenable number.
21032213 is a deficient number, since it is larger than the sum of its proper divisors (1489027).
21032213 is a wasteful number, since it uses less digits than its factorization.
21032213 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 14007.
The product of its (nonzero) digits is 72, while the sum is 14.
The square root of 21032213 is about 4586.0890745820.
The cubic root of 21032213 is about 276.0334141790.
Adding to 21032213 its reverse (31223012), we get a palindrome (52255225).
It can be divided in two parts, 210 and 32213, that added together give a palindrome (32423).
The spelling of 21032213 in words is "twenty-one million, thirty-two thousand, two hundred thirteen".