21533245 has 8 divisors (see below), whose sum is σ = 25893720. Its totient is φ = 17190720.

The previous prime is 21533227. The next prime is 21533257. The reversal of 21533245 is 54233512.

It can be written as a sum of positive squares in 4 ways, for example, as 8421604 + 13111641 = 2902^2 + 3621^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21533245 - 2⁷ = 21533117 is a prime.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 1686 + ... + 6775.

It is an arithmetic number, because the mean of its divisors is an integer number (3236715).

Almost surely, 2^21533245 is an apocalyptic number.

It is an amenable number.

21533245 is a deficient number, since it is larger than the sum of its proper divisors (4360475).

21533245 is an equidigital number, since it uses as much as digits as its factorization.

21533245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8975.

The product of its digits is 3600, while the sum is 25.

The square root of 21533245 is about 4640.3927635492. The cubic root of 21533245 is about 278.2081364898.

Adding to 21533245 its reverse (54233512), we get a palindrome (75766757).

The spelling of 21533245 in words is "twenty-one million, five hundred thirty-three thousand, two hundred forty-five".