21206133 has 24 divisors (see below), whose sum is σ = 33182240. Its totient is φ = 12972960.

The previous prime is 21206131. The next prime is 21206173. The reversal of 21206133 is 33160212.

It is not a de Polignac number, because 21206133 - 2¹ = 21206131 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21206131) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24258 + ... + 25116.

Almost surely, 2^21206133 is an apocalyptic number.

It is an amenable number.

21206133 is a deficient number, since it is larger than the sum of its proper divisors (11976107).

21206133 is a wasteful number, since it uses less digits than its factorization.

21206133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1089 (or 1086 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21206133 is about 4605.0117263694. The cubic root of 21206133 is about 276.7921868792.

Adding to 21206133 its reverse (33160212), we get a palindrome (54366345).

The spelling of 21206133 in words is "twenty-one million, two hundred six thousand, one hundred thirty-three".