21133744 has 10 divisors (see below), whose sum is σ = 40946660. Its totient is φ = 10566864.

The previous prime is 21133733. The next prime is 21133747. The reversal of 21133744 is 44733112.

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 (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660414 + ... + 660445.

It is an arithmetic number, because the mean of its divisors is an integer number (4094666).

Almost surely, 2^21133744 is an apocalyptic number.

It is an amenable number.

21133744 is a deficient number, since it is larger than the sum of its proper divisors (19812916).

21133744 is a wasteful number, since it uses less digits than its factorization.

21133744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1320867 (or 1320861 counting only the distinct ones).

The product of its digits is 2016, while the sum is 25.

The square root of 21133744 is about 4597.1452011004. The cubic root of 21133744 is about 276.4768763356.

Adding to 21133744 its reverse (44733112), we get a palindrome (65866856).

It can be divided in two parts, 211337 and 44, that multiplied together give a triangular number (9298828 = T₄₃₁₂).

The spelling of 21133744 in words is "twenty-one million, one hundred thirty-three thousand, seven hundred forty-four".