21073306 has 4 divisors (see below), whose sum is σ = 31609962. Its totient is φ = 10536652.

The previous prime is 21073301. The next prime is 21073307. The reversal of 21073306 is 60337012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14130081 + 6943225 = 3759^2 + 2635^2 .

It is not an unprimeable number, because it can be changed into a prime (21073301) 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 as a sum of consecutive naturals, namely, 5268325 + ... + 5268328.

Almost surely, 2^21073306 is an apocalyptic number.

21073306 is a deficient number, since it is larger than the sum of its proper divisors (10536656).

21073306 is a wasteful number, since it uses less digits than its factorization.

21073306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10536655.

The product of its (nonzero) digits is 756, while the sum is 22.

The square root of 21073306 is about 4590.5670673676. The cubic root of 21073306 is about 276.2130697341.

The spelling of 21073306 in words is "twenty-one million, seventy-three thousand, three hundred six".