21242773 has 12 divisors (see below), whose sum is σ = 22286880. Its totient is φ = 20241072.

The previous prime is 21242759. The next prime is 21242783. The reversal of 21242773 is 37724212.

It is a de Polignac number, because none of the positive numbers 2^k-21242773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242713) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 80640 + ... + 80902.

It is an arithmetic number, because the mean of its divisors is an integer number (1857240).

Almost surely, 2^21242773 is an apocalyptic number.

It is an amenable number.

21242773 is a deficient number, since it is larger than the sum of its proper divisors (1044107).

21242773 is an equidigital number, since it uses as much as digits as its factorization.

21242773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396 (or 359 counting only the distinct ones).

The product of its digits is 4704, while the sum is 28.

The square root of 21242773 is about 4608.9882837777. The cubic root of 21242773 is about 276.9515091909.

Adding to 21242773 its reverse (37724212), we get a palindrome (58966985).

The spelling of 21242773 in words is "twenty-one million, two hundred forty-two thousand, seven hundred seventy-three".