21120858 has 96 divisors (see below), whose sum is σ = 54336960. Its totient is φ = 6026400.

The previous prime is 21120833. The next prime is 21120893. The reversal of 21120858 is 85802112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 570816 + ... + 570852.

It is an arithmetic number, because the mean of its divisors is an integer number (566010).

Almost surely, 2^21120858 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120858, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27168480).

21120858 is an abundant number, since it is smaller than the sum of its proper divisors (33216102).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21120858 is a wasteful number, since it uses less digits than its factorization.

21120858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 21120858 is about 4595.7434654254. The cubic root of 21120858 is about 276.4206722957.

The spelling of 21120858 in words is "twenty-one million, one hundred twenty thousand, eight hundred fifty-eight".