21145535 has 32 divisors (see below), whose sum is σ = 28200960. Its totient is φ = 15155712.

The previous prime is 21145519. The next prime is 21145543. The reversal of 21145535 is 53554112.

It is a cyclic number.

It is not a de Polignac number, because 21145535 - 2⁴ = 21145519 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 267626 + ... + 267704.

It is an arithmetic number, because the mean of its divisors is an integer number (881280).

Almost surely, 2^21145535 is an apocalyptic number.

21145535 is a deficient number, since it is larger than the sum of its proper divisors (7055425).

21145535 is a wasteful number, since it uses less digits than its factorization.

21145535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215.

The product of its digits is 3000, while the sum is 26.

The square root of 21145535 is about 4598.4274485959. The cubic root of 21145535 is about 276.5282843708.

Adding to 21145535 its reverse (53554112), we get a palindrome (74699647).

The spelling of 21145535 in words is "twenty-one million, one hundred forty-five thousand, five hundred thirty-five".