21643135 has 12 divisors (see below), whose sum is σ = 26903448. Its totient is φ = 16714208.

The previous prime is 21643129. The next prime is 21643183. The reversal of 21643135 is 53134612.

It is not a de Polignac number, because 21643135 - 2⁵ = 21643103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1632 + ... + 6778.

It is an arithmetic number, because the mean of its divisors is an integer number (2241954).

Almost surely, 2^21643135 is an apocalyptic number.

21643135 is a deficient number, since it is larger than the sum of its proper divisors (5260313).

21643135 is an equidigital number, since it uses as much as digits as its factorization.

21643135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5210 (or 5181 counting only the distinct ones).

The product of its digits is 2160, while the sum is 25.

The square root of 21643135 is about 4652.2182880858. The cubic root of 21643135 is about 278.6805909484.

Adding to 21643135 its reverse (53134612), we get a palindrome (74777747).

The spelling of 21643135 in words is "twenty-one million, six hundred forty-three thousand, one hundred thirty-five".