21404055 has 16 divisors (see below), whose sum is σ = 34633440. Its totient is φ = 11286528.

The previous prime is 21404029. The next prime is 21404063. The reversal of 21404055 is 55040412.

It is not a de Polignac number, because 21404055 - 2¹³ = 21395863 is a prime.

It is a congruent number.

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, 6682 + ... + 9351.

It is an arithmetic number, because the mean of its divisors is an integer number (2164590).

Almost surely, 2^21404055 is an apocalyptic number.

21404055 is a deficient number, since it is larger than the sum of its proper divisors (13229385).

21404055 is a wasteful number, since it uses less digits than its factorization.

21404055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16130.

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 21404055 is about 4626.4516640726. The cubic root of 21404055 is about 277.6506446078.

Adding to 21404055 its reverse (55040412), we get a palindrome (76444467).

The spelling of 21404055 in words is "twenty-one million, four hundred four thousand, fifty-five".