21020396 has 6 divisors (see below), whose sum is σ = 36785700. Its totient is φ = 10510196.

The previous prime is 21020369. The next prime is 21020407. The reversal of 21020396 is 69302012.

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, 2627546 + ... + 2627553.

It is an arithmetic number, because the mean of its divisors is an integer number (6130950).

Almost surely, 2^21020396 is an apocalyptic number.

It is an amenable number.

21020396 is a deficient number, since it is larger than the sum of its proper divisors (15765304).

21020396 is a wasteful number, since it uses less digits than its factorization.

21020396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5255103 (or 5255101 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 21020396 is about 4584.8005409178. The cubic root of 21020396 is about 275.9817078124.

The spelling of 21020396 in words is "twenty-one million, twenty thousand, three hundred ninety-six".