21124135 has 4 divisors (see below), whose sum is σ = 25348968. Its totient is φ = 16899304.

The previous prime is 21124123. The next prime is 21124141. The reversal of 21124135 is 53142112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21124135 - 2⁷ = 21124007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2112409 + ... + 2112418.

It is an arithmetic number, because the mean of its divisors is an integer number (6337242).

Almost surely, 2^21124135 is an apocalyptic number.

21124135 is a deficient number, since it is larger than the sum of its proper divisors (4224833).

21124135 is an equidigital number, since it uses as much as digits as its factorization.

21124135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4224832.

The product of its digits is 240, while the sum is 19.

The square root of 21124135 is about 4596.0999771545. The cubic root of 21124135 is about 276.4349675435.

Adding to 21124135 its reverse (53142112), we get a palindrome (74266247).

The spelling of 21124135 in words is "twenty-one million, one hundred twenty-four thousand, one hundred thirty-five".