21660773 has 4 divisors (see below), whose sum is σ = 21935040. Its totient is φ = 21386508.

The previous prime is 21660761. The next prime is 21660791. The reversal of 21660773 is 37706612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21660773 - 2⁴ = 21660757 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 (21660713) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 137015 + ... + 137172.

It is an arithmetic number, because the mean of its divisors is an integer number (5483760).

Almost surely, 2^21660773 is an apocalyptic number.

It is an amenable number.

21660773 is a deficient number, since it is larger than the sum of its proper divisors (274267).

21660773 is an equidigital number, since it uses as much as digits as its factorization.

21660773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274266.

The product of its (nonzero) digits is 10584, while the sum is 32.

The square root of 21660773 is about 4654.1135568441. The cubic root of 21660773 is about 278.7562736628.

The spelling of 21660773 in words is "twenty-one million, six hundred sixty thousand, seven hundred seventy-three".