21065404 has 6 divisors (see below), whose sum is σ = 36864464. Its totient is φ = 10532700.

The previous prime is 21065381. The next prime is 21065413. The reversal of 21065404 is 40456012.

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 as a sum of consecutive naturals, namely, 2633172 + ... + 2633179.

Almost surely, 2^21065404 is an apocalyptic number.

It is an amenable number.

21065404 is a deficient number, since it is larger than the sum of its proper divisors (15799060).

21065404 is a wasteful number, since it uses less digits than its factorization.

21065404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5266355 (or 5266353 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21065404 is about 4589.7063086869. The cubic root of 21065404 is about 276.1785409239.

The spelling of 21065404 in words is "twenty-one million, sixty-five thousand, four hundred four".