21746513 has 2 divisors, whose sum is σ = 21746514. Its totient is φ = 21746512.

The previous prime is 21746509. The next prime is 21746533. The reversal of 21746513 is 31564712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16875664 + 4870849 = 4108^2 + 2207^2 .

It is a cyclic number.

It is not a de Polignac number, because 21746513 - 2² = 21746509 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21746503) 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, 10873256 + 10873257.

It is an arithmetic number, because the mean of its divisors is an integer number (10873257).

Almost surely, 2^21746513 is an apocalyptic number.

It is an amenable number.

21746513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21746513 is an equidigital number, since it uses as much as digits as its factorization.

21746513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 29.

The square root of 21746513 is about 4663.3156659184. The cubic root of 21746513 is about 279.1235904526.

The spelling of 21746513 in words is "twenty-one million, seven hundred forty-six thousand, five hundred thirteen".