21058855 has 8 divisors (see below), whose sum is σ = 25391664. Its totient is φ = 16766400.

The previous prime is 21058853. The next prime is 21058907. The reversal of 21058855 is 55885012.

It is a happy number.

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

It is not a de Polignac number, because 21058855 - 2¹ = 21058853 is a prime.

It is a super-2 number, since 2×21058855² = 886950747822050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21058855.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21058853) 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, 8926 + ... + 11035.

It is an arithmetic number, because the mean of its divisors is an integer number (3173958).

Almost surely, 2^21058855 is an apocalyptic number.

21058855 is a deficient number, since it is larger than the sum of its proper divisors (4332809).

21058855 is a wasteful number, since it uses less digits than its factorization.

21058855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20177.

The product of its (nonzero) digits is 16000, while the sum is 34.

The square root of 21058855 is about 4588.9928088852. The cubic root of 21058855 is about 276.1499176778.

The spelling of 21058855 in words is "twenty-one million, fifty-eight thousand, eight hundred fifty-five".