21404135 has 4 divisors (see below), whose sum is σ = 25684968. Its totient is φ = 17123304.

The previous prime is 21404101. The next prime is 21404147. The reversal of 21404135 is 53140412.

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 21404135 - 2¹⁰ = 21403111 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, 2140409 + ... + 2140418.

It is an arithmetic number, because the mean of its divisors is an integer number (6421242).

Almost surely, 2^21404135 is an apocalyptic number.

21404135 is a deficient number, since it is larger than the sum of its proper divisors (4280833).

21404135 is an equidigital number, since it uses as much as digits as its factorization.

21404135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4280832.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21404135 is about 4626.4603099994. The cubic root of 21404135 is about 277.6509905240.

Adding to 21404135 its reverse (53140412), we get a palindrome (74544547).

The spelling of 21404135 in words is "twenty-one million, four hundred four thousand, one hundred thirty-five".