21408104 has 16 divisors (see below), whose sum is σ = 41435520. Its totient is φ = 10358640.

The previous prime is 21408103. The next prime is 21408113. The reversal of 21408104 is 40180412.

It is not an unprimeable number, because it can be changed into a prime (21408103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42914 + ... + 43409.

It is an arithmetic number, because the mean of its divisors is an integer number (2589720).

Almost surely, 2^21408104 is an apocalyptic number.

It is an amenable number.

21408104 is a deficient number, since it is larger than the sum of its proper divisors (20027416).

21408104 is a wasteful number, since it uses less digits than its factorization.

21408104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86360 (or 86356 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21408104 is about 4626.8892357609. The cubic root of 21408104 is about 277.6681512061.

Adding to 21408104 its reverse (40180412), we get a palindrome (61588516).

It can be divided in two parts, 21408 and 104, that added together give a palindrome (21512).

The spelling of 21408104 in words is "twenty-one million, four hundred eight thousand, one hundred four".