21116709 has 12 divisors (see below), whose sum is σ = 30662476. Its totient is φ = 14003712.

The previous prime is 21116707. The next prime is 21116713. The reversal of 21116709 is 90761112.

It can be written as a sum of positive squares in 2 ways, for example, as 2712609 + 18404100 = 1647^2 + 4290^2 .

It is not a de Polignac number, because 21116709 - 2¹ = 21116707 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21116701) 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 in 11 ways as a sum of consecutive naturals, for example, 4342 + ... + 7815.

Almost surely, 2^21116709 is an apocalyptic number.

It is an amenable number.

21116709 is a deficient number, since it is larger than the sum of its proper divisors (9545767).

21116709 is a wasteful number, since it uses less digits than its factorization.

21116709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12356 (or 12353 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 27.

The square root of 21116709 is about 4595.2920473023. The cubic root of 21116709 is about 276.4025710033.

The spelling of 21116709 in words is "twenty-one million, one hundred sixteen thousand, seven hundred nine".