21136716 has 18 divisors (see below), whose sum is σ = 53429012. Its totient is φ = 7045560.

The previous prime is 21136681. The next prime is 21136723. The reversal of 21136716 is 61763112.

It is a tau number, because it is divible by the number of its divisors (18).

It is a self number, because there is not a number n which added to its sum of digits gives 21136716.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 293530 + ... + 293601.

Almost surely, 2^21136716 is an apocalyptic number.

It is an amenable number.

21136716 is an abundant number, since it is smaller than the sum of its proper divisors (32292296).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21136716 is a wasteful number, since it uses less digits than its factorization.

21136716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 587141 (or 587136 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21136716 is about 4597.4684338231. The cubic root of 21136716 is about 276.4898358749.

Adding to 21136716 its reverse (61763112), we get a palindrome (82899828).

The spelling of 21136716 in words is "twenty-one million, one hundred thirty-six thousand, seven hundred sixteen".