21707773 has 2 divisors, whose sum is σ = 21707774. Its totient is φ = 21707772.

The previous prime is 21707771. The next prime is 21707779. The reversal of 21707773 is 37770712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10936249 + 10771524 = 3307^2 + 3282^2 .

It is a cyclic number.

It is not a de Polignac number, because 21707773 - 2¹ = 21707771 is a prime.

Together with 21707771, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21707771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10853886 + 10853887.

It is an arithmetic number, because the mean of its divisors is an integer number (10853887).

Almost surely, 2^21707773 is an apocalyptic number.

It is an amenable number.

21707773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21707773 is an equidigital number, since it uses as much as digits as its factorization.

21707773 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14406, while the sum is 34.

The square root of 21707773 is about 4659.1601174461. The cubic root of 21707773 is about 278.9577450856.

The spelling of 21707773 in words is "twenty-one million, seven hundred seven thousand, seven hundred seventy-three".