21044205 has 80 divisors (see below), whose sum is σ = 46510464. Its totient is φ = 8864640.

The previous prime is 21044197. The next prime is 21044213. The reversal of 21044205 is 50244012.

It is an interprime number because it is at equal distance from previous prime (21044197) and next prime (21044213).

It is not a de Polignac number, because 21044205 - 2³ = 21044197 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 79 ways as a sum of consecutive naturals, for example, 36570 + ... + 37140.

Almost surely, 2^21044205 is an apocalyptic number.

It is an amenable number.

21044205 is an abundant number, since it is smaller than the sum of its proper divisors (25466259).

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

21044205 is a wasteful number, since it uses less digits than its factorization.

21044205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608 (or 599 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 21044205 is about 4587.3963203543. The cubic root of 21044205 is about 276.0858664780.

Adding to 21044205 its reverse (50244012), we get a palindrome (71288217).

The spelling of 21044205 in words is "twenty-one million, forty-four thousand, two hundred five".