21022306 has 4 divisors (see below), whose sum is σ = 31533462. Its totient is φ = 10511152.

The previous prime is 21022279. The next prime is 21022357. The reversal of 21022306 is 60322012.

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., 21022225 + 81 = 4585^2 + 9^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21022306.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5255575 + ... + 5255578.

Almost surely, 2^21022306 is an apocalyptic number.

21022306 is a deficient number, since it is larger than the sum of its proper divisors (10511156).

21022306 is a wasteful number, since it uses less digits than its factorization.

21022306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10511155.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21022306 is about 4585.0088331431. The cubic root of 21022306 is about 275.9900665052.

Adding to 21022306 its reverse (60322012), we get a palindrome (81344318).

The spelling of 21022306 in words is "twenty-one million, twenty-two thousand, three hundred six".