21133145 has 16 divisors (see below), whose sum is σ = 28123200. Its totient is φ = 15115200.

The previous prime is 21133121. The next prime is 21133153. The reversal of 21133145 is 54133112.

It is not a de Polignac number, because 21133145 - 2¹² = 21129049 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 206 + ... + 6504.

It is an arithmetic number, because the mean of its divisors is an integer number (1757700).

Almost surely, 2^21133145 is an apocalyptic number.

It is an amenable number.

21133145 is a deficient number, since it is larger than the sum of its proper divisors (6990055).

21133145 is a wasteful number, since it uses less digits than its factorization.

21133145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6376.

The product of its digits is 360, while the sum is 20.

The square root of 21133145 is about 4597.0800515110. The cubic root of 21133145 is about 276.4742642221.

Adding to 21133145 its reverse (54133112), we get a palindrome (75266257).

The spelling of 21133145 in words is "twenty-one million, one hundred thirty-three thousand, one hundred forty-five".