21126939 has 8 divisors (see below), whose sum is σ = 28196112. Its totient is φ = 14071200.

The previous prime is 21126929. The next prime is 21126943. The reversal of 21126939 is 93962112.

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

It is not a de Polignac number, because 21126939 - 2⁸ = 21126683 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21126929) 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, 1197 + ... + 6609.

It is an arithmetic number, because the mean of its divisors is an integer number (3524514).

Almost surely, 2^21126939 is an apocalyptic number.

21126939 is a deficient number, since it is larger than the sum of its proper divisors (7069173).

21126939 is a wasteful number, since it uses less digits than its factorization.

21126939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6717.

The product of its digits is 5832, while the sum is 33.

The square root of 21126939 is about 4596.4050082646. The cubic root of 21126939 is about 276.4471982511.

The spelling of 21126939 in words is "twenty-one million, one hundred twenty-six thousand, nine hundred thirty-nine".