21404588 has 6 divisors (see below), whose sum is σ = 37458036. Its totient is φ = 10702292.

The previous prime is 21404569. The next prime is 21404597. The reversal of 21404588 is 88540412.

It is a happy 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 as a sum of consecutive naturals, namely, 2675570 + ... + 2675577.

It is an arithmetic number, because the mean of its divisors is an integer number (6243006).

Almost surely, 2^21404588 is an apocalyptic number.

It is an amenable number.

21404588 is a deficient number, since it is larger than the sum of its proper divisors (16053448).

21404588 is a wasteful number, since it uses less digits than its factorization.

21404588 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5351151 (or 5351149 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 32.

The square root of 21404588 is about 4626.5092672554. The cubic root of 21404588 is about 277.6529492578.

The spelling of 21404588 in words is "twenty-one million, four hundred four thousand, five hundred eighty-eight".