21118736 has 20 divisors (see below), whose sum is σ = 41058012. Its totient is φ = 10523136.

The previous prime is 21118733. The next prime is 21118739. The reversal of 21118736 is 63781112.

It is an interprime number because it is at equal distance from previous prime (21118733) and next prime (21118739).

It can be written as a sum of positive squares in 2 ways, for example, as 7840000 + 13278736 = 2800^2 + 3644^2 .

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21118699 and 21118708.

It is not an unprimeable number, because it can be changed into a prime (21118733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2900 + ... + 7116.

Almost surely, 2^21118736 is an apocalyptic number.

It is an amenable number.

21118736 is a deficient number, since it is larger than the sum of its proper divisors (19939276).

21118736 is a wasteful number, since it uses less digits than its factorization.

21118736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4538 (or 4532 counting only the distinct ones).

The product of its digits is 2016, while the sum is 29.

The square root of 21118736 is about 4595.5125938245. The cubic root of 21118736 is about 276.4114147123.

Adding to 21118736 its reverse (63781112), we get a palindrome (84899848).

The spelling of 21118736 in words is "twenty-one million, one hundred eighteen thousand, seven hundred thirty-six".