21037306 has 4 divisors (see below), whose sum is σ = 31555962. Its totient is φ = 10518652.

The previous prime is 21037301. The next prime is 21037339. The reversal of 21037306 is 60373012.

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., 19847025 + 1190281 = 4455^2 + 1091^2 .

It is not an unprimeable number, because it can be changed into a prime (21037301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5259325 + ... + 5259328.

Almost surely, 2^21037306 is an apocalyptic number.

21037306 is a deficient number, since it is larger than the sum of its proper divisors (10518656).

21037306 is a wasteful number, since it uses less digits than its factorization.

21037306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10518655.

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

The square root of 21037306 is about 4586.6443071160. The cubic root of 21037306 is about 276.0556930949.

It can be divided in two parts, 2103 and 7306, that added together give a square (9409 = 97²).

The spelling of 21037306 in words is "twenty-one million, thirty-seven thousand, three hundred six".