21306116 has 12 divisors (see below), whose sum is σ = 40153932. Its totient is φ = 9833568.

The previous prime is 21306091. The next prime is 21306143. The reversal of 21306116 is 61160312.

It can be written as a sum of positive squares in 2 ways, for example, as 1020100 + 20286016 = 1010^2 + 4504^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 204815 + ... + 204918.

It is an arithmetic number, because the mean of its divisors is an integer number (3346161).

Almost surely, 2^21306116 is an apocalyptic number.

21306116 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21306116 is a deficient number, since it is larger than the sum of its proper divisors (18847816).

21306116 is a wasteful number, since it uses less digits than its factorization.

21306116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409750 (or 409748 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21306116 is about 4615.8548504042. The cubic root of 21306116 is about 277.2265130147.

Adding to 21306116 its reverse (61160312), we get a palindrome (82466428).

The spelling of 21306116 in words is "twenty-one million, three hundred six thousand, one hundred sixteen".