21220933 has 4 divisors (see below), whose sum is σ = 21237120. Its totient is φ = 21204748.

The previous prime is 21220921. The next prime is 21220937. The reversal of 21220933 is 33902212.

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 a de Polignac number, because none of the positive numbers 2^k-21220933 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 (21220937) 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, 5935 + ... + 8812.

It is an arithmetic number, because the mean of its divisors is an integer number (5309280).

Almost surely, 2^21220933 is an apocalyptic number.

It is an amenable number.

21220933 is a deficient number, since it is larger than the sum of its proper divisors (16187).

21220933 is a wasteful number, since it uses less digits than its factorization.

21220933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16186.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 21220933 is about 4606.6183909675. The cubic root of 21220933 is about 276.8565640373.

The spelling of 21220933 in words is "twenty-one million, two hundred twenty thousand, nine hundred thirty-three".