21075705 has 48 divisors (see below), whose sum is σ = 43580160. Its totient is φ = 9212544.

The previous prime is 21075697. The next prime is 21075713. The reversal of 21075705 is 50757012.

It is an interprime number because it is at equal distance from previous prime (21075697) and next prime (21075713).

It is not a de Polignac number, because 21075705 - 2³ = 21075697 is a prime.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 5791 + ... + 8699.

It is an arithmetic number, because the mean of its divisors is an integer number (907920).

Almost surely, 2^21075705 is an apocalyptic number.

It is an amenable number.

21075705 is an abundant number, since it is smaller than the sum of its proper divisors (22504455).

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

21075705 is a wasteful number, since it uses less digits than its factorization.

21075705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2950 (or 2947 counting only the distinct ones).

The product of its (nonzero) digits is 2450, while the sum is 27.

The square root of 21075705 is about 4590.8283566258. The cubic root of 21075705 is about 276.2235507665.

The spelling of 21075705 in words is "twenty-one million, seventy-five thousand, seven hundred five".