21020713 has 8 divisors (see below), whose sum is σ = 24053760. Its totient is φ = 17995200.

The previous prime is 21020683. The next prime is 21020719. The reversal of 21020713 is 31702012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21020713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6753 + ... + 9361.

It is an arithmetic number, because the mean of its divisors is an integer number (3006720).

Almost surely, 2^21020713 is an apocalyptic number.

It is an amenable number.

21020713 is a deficient number, since it is larger than the sum of its proper divisors (3033047).

21020713 is a wasteful number, since it uses less digits than its factorization.

21020713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3767.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21020713 is about 4584.8351115389. The cubic root of 21020713 is about 275.9830951279.

Adding to 21020713 its reverse (31702012), we get a palindrome (52722725).

The spelling of 21020713 in words is "twenty-one million, twenty thousand, seven hundred thirteen".