21075858 has 24 divisors (see below), whose sum is σ = 46217808. Its totient is φ = 6940152.

The previous prime is 21075851. The next prime is 21075863. The reversal of 21075858 is 85857012.

It is not an unprimeable number, because it can be changed into a prime (21075851) 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 11 ways as a sum of consecutive naturals, for example, 5560 + ... + 8547.

It is an arithmetic number, because the mean of its divisors is an integer number (1925742).

Almost surely, 2^21075858 is an apocalyptic number.

21075858 is an abundant number, since it is smaller than the sum of its proper divisors (25141950).

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

21075858 is a wasteful number, since it uses less digits than its factorization.

21075858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14198 (or 14195 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The square root of 21075858 is about 4590.8450202550. The cubic root of 21075858 is about 276.2242191839.

The spelling of 21075858 in words is "twenty-one million, seventy-five thousand, eight hundred fifty-eight".