21698713 has 2 divisors, whose sum is σ = 21698714. Its totient is φ = 21698712.

The previous prime is 21698711. The next prime is 21698731. The reversal of 21698713 is 31789612.

Together with next prime (21698731) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18429849 + 3268864 = 4293^2 + 1808^2 .

It is a cyclic number.

It is not a de Polignac number, because 21698713 - 2¹ = 21698711 is a prime.

Together with 21698711, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21698711) 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 as a sum of consecutive naturals, namely, 10849356 + 10849357.

It is an arithmetic number, because the mean of its divisors is an integer number (10849357).

Almost surely, 2^21698713 is an apocalyptic number.

It is an amenable number.

21698713 is a deficient number, since it is larger than the sum of its proper divisors (1).

21698713 is an equidigital number, since it uses as much as digits as its factorization.

21698713 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 37.

The square root of 21698713 is about 4658.1877377366. The cubic root of 21698713 is about 278.9189308959.

The spelling of 21698713 in words is "twenty-one million, six hundred ninety-eight thousand, seven hundred thirteen".