21304786 has 16 divisors (see below), whose sum is σ = 32399640. Its totient is φ = 10506240.

The previous prime is 21304783. The next prime is 21304793. The reversal of 21304786 is 68740312.

It can be written as a sum of positive squares in 4 ways, for example, as 20875761 + 429025 = 4569^2 + 655^2 .

It is not an unprimeable number, because it can be changed into a prime (21304783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82770 + ... + 83026.

Almost surely, 2^21304786 is an apocalyptic number.

21304786 is a deficient number, since it is larger than the sum of its proper divisors (11094854).

21304786 is a wasteful number, since it uses less digits than its factorization.

21304786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 21304786 is about 4615.7107795008. The cubic root of 21304786 is about 277.2207444217.

The spelling of 21304786 in words is "twenty-one million, three hundred four thousand, seven hundred eighty-six".