21058789 has 8 divisors (see below), whose sum is σ = 21658392. Its totient is φ = 20463360.

The previous prime is 21058787. The next prime is 21058819. The reversal of 21058789 is 98785012.

It can be written as a sum of positive squares in 4 ways, for example, as 128164 + 20930625 = 358^2 + 4575^2 .

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 21058789 - 2¹ = 21058787 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21058781) 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 in 7 ways as a sum of consecutive naturals, for example, 11137 + ... + 12889.

It is an arithmetic number, because the mean of its divisors is an integer number (2707299).

Almost surely, 2^21058789 is an apocalyptic number.

It is an amenable number.

21058789 is a deficient number, since it is larger than the sum of its proper divisors (599603).

21058789 is a wasteful number, since it uses less digits than its factorization.

21058789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2087.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 21058789 is about 4588.9856177591. The cubic root of 21058789 is about 276.1496291861.

The spelling of 21058789 in words is "twenty-one million, fifty-eight thousand, seven hundred eighty-nine".