21707573 has 8 divisors (see below), whose sum is σ = 23005080. Its totient is φ = 20446720.

The previous prime is 21707549. The next prime is 21707579. The reversal of 21707573 is 37570712.

It can be written as a sum of positive squares in 4 ways, for example, as 10609 + 21696964 = 103^2 + 4658^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21707573 - 2²⁰ = 20658997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21707579) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7940 + ... + 10317.

It is an arithmetic number, because the mean of its divisors is an integer number (2875635).

Almost surely, 2^21707573 is an apocalyptic number.

It is an amenable number.

21707573 is a deficient number, since it is larger than the sum of its proper divisors (1297507).

21707573 is a wasteful number, since it uses less digits than its factorization.

21707573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18327.

The product of its (nonzero) digits is 10290, while the sum is 32.

The square root of 21707573 is about 4659.1386543008. The cubic root of 21707573 is about 278.9568883768.

The spelling of 21707573 in words is "twenty-one million, seven hundred seven thousand, five hundred seventy-three".