21075999 has 8 divisors (see below), whose sum is σ = 32115840. Its totient is φ = 12043416.

The previous prime is 21075991. The next prime is 21076019. The reversal of 21075999 is 99957012.

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

It is not a de Polignac number, because 21075999 - 2³ = 21075991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21075999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21075991) 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, 501789 + ... + 501830.

It is an arithmetic number, because the mean of its divisors is an integer number (4014480).

Almost surely, 2^21075999 is an apocalyptic number.

21075999 is a deficient number, since it is larger than the sum of its proper divisors (11039841).

21075999 is a wasteful number, since it uses less digits than its factorization.

21075999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1003629.

The product of its (nonzero) digits is 51030, while the sum is 42.

The square root of 21075999 is about 4590.8603768793. The cubic root of 21075999 is about 276.2248351735.

The spelling of 21075999 in words is "twenty-one million, seventy-five thousand, nine hundred ninety-nine".