21063730 has 16 divisors (see below), whose sum is σ = 38940120. Its totient is φ = 8197632.

The previous prime is 21063703. The next prime is 21063733. The reversal of 21063730 is 3736012.

It can be written as a sum of positive squares in 4 ways, for example, as 14768649 + 6295081 = 3843^2 + 2509^2 .

It is not an unprimeable number, because it can be changed into a prime (21063733) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28095 + ... + 28834.

Almost surely, 2^21063730 is an apocalyptic number.

21063730 is a deficient number, since it is larger than the sum of its proper divisors (17876390).

21063730 is a wasteful number, since it uses less digits than its factorization.

21063730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56973.

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

The square root of 21063730 is about 4589.5239404540. The cubic root of 21063730 is about 276.1712250563.

Adding to 21063730 its reverse (3736012), we get a palindrome (24799742).

The spelling of 21063730 in words is "twenty-one million, sixty-three thousand, seven hundred thirty".