21133749 has 24 divisors (see below), whose sum is σ = 35303520. Its totient is φ = 11146464.

The previous prime is 21133747. The next prime is 21133753. The reversal of 21133749 is 94733112.

It is not a de Polignac number, because 21133749 - 2¹ = 21133747 is a prime.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3619 + ... + 7440.

It is an arithmetic number, because the mean of its divisors is an integer number (1470980).

Almost surely, 2^21133749 is an apocalyptic number.

It is an amenable number.

21133749 is a deficient number, since it is larger than the sum of its proper divisors (14169771).

21133749 is a wasteful number, since it uses less digits than its factorization.

21133749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11089 (or 11082 counting only the distinct ones).

The product of its digits is 4536, while the sum is 30.

The square root of 21133749 is about 4597.1457449161. The cubic root of 21133749 is about 276.4768981393.

The spelling of 21133749 in words is "twenty-one million, one hundred thirty-three thousand, seven hundred forty-nine".