21138933 has 8 divisors (see below), whose sum is σ = 28663200. Its totient is φ = 13853648.

The previous prime is 21138917. The next prime is 21138937. The reversal of 21138933 is 33983112.

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 21138933 - 2⁴ = 21138917 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21138933.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21138937) 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 7 ways as a sum of consecutive naturals, for example, 59538 + ... + 59891.

It is an arithmetic number, because the mean of its divisors is an integer number (3582900).

Almost surely, 2^21138933 is an apocalyptic number.

It is an amenable number.

21138933 is a deficient number, since it is larger than the sum of its proper divisors (7524267).

21138933 is a wasteful number, since it uses less digits than its factorization.

21138933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119491.

The product of its digits is 3888, while the sum is 30.

The square root of 21138933 is about 4597.7095384550. The cubic root of 21138933 is about 276.4995024118.

The spelling of 21138933 in words is "twenty-one million, one hundred thirty-eight thousand, nine hundred thirty-three".