21700513 has 2 divisors, whose sum is σ = 21700514. Its totient is φ = 21700512.

The previous prime is 21700501. The next prime is 21700529. The reversal of 21700513 is 31500712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13307904 + 8392609 = 3648^2 + 2897^2 .

It is a cyclic number.

It is not a de Polignac number, because 21700513 - 2⁹ = 21700001 is a prime.

It is not a weakly prime, because it can be changed into another prime (21700573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10850256 + 10850257.

It is an arithmetic number, because the mean of its divisors is an integer number (10850257).

Almost surely, 2^21700513 is an apocalyptic number.

It is an amenable number.

21700513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21700513 is an equidigital number, since it uses as much as digits as its factorization.

21700513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 210, while the sum is 19.

The square root of 21700513 is about 4658.3809419153. The cubic root of 21700513 is about 278.9266431842.

The spelling of 21700513 in words is "twenty-one million, seven hundred thousand, five hundred thirteen".