21130733 has 8 divisors (see below), whose sum is σ = 22911000. Its totient is φ = 19372608.

The previous prime is 21130727. The next prime is 21130741. The reversal of 21130733 is 33703112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 537289 + 20593444 = 733^2 + 4538^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21130733 - 2⁸ = 21130477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21130783) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3518 + ... + 7391.

It is an arithmetic number, because the mean of its divisors is an integer number (2863875).

Almost surely, 2^21130733 is an apocalyptic number.

It is an amenable number.

21130733 is a deficient number, since it is larger than the sum of its proper divisors (1780267).

21130733 is a wasteful number, since it uses less digits than its factorization.

21130733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11071.

The product of its (nonzero) digits is 378, while the sum is 20.

The square root of 21130733 is about 4596.8177035858. The cubic root of 21130733 is about 276.4637454959.

Adding to 21130733 its reverse (33703112), we get a palindrome (54833845).

The spelling of 21130733 in words is "twenty-one million, one hundred thirty thousand, seven hundred thirty-three".