21404442 has 8 divisors (see below), whose sum is σ = 42808896. Its totient is φ = 7134812.

The previous prime is 21404437. The next prime is 21404459. The reversal of 21404442 is 24440412.

It is a sphenic number, since it is the product of 3 distinct primes.

21404442 is an admirable 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, 1783698 + ... + 1783709.

It is an arithmetic number, because the mean of its divisors is an integer number (5351112).

Almost surely, 2^21404442 is an apocalyptic number.

21404442 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21404442 is a wasteful number, since it uses less digits than its factorization.

21404442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3567412.

The product of its (nonzero) digits is 1024, while the sum is 21.

The square root of 21404442 is about 4626.4934885937. The cubic root of 21404442 is about 277.6523179691.

Adding to 21404442 its reverse (24440412), we get a palindrome (45844854).

The spelling of 21404442 in words is "twenty-one million, four hundred four thousand, four hundred forty-two".