21210075 has 36 divisors (see below), whose sum is σ = 38388168. Its totient is φ = 11193600.

The previous prime is 21210053. The next prime is 21210089. The reversal of 21210075 is 57001212.

It is not a de Polignac number, because 21210075 - 2⁶ = 21210011 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 23635 + ... + 24515.

It is an arithmetic number, because the mean of its divisors is an integer number (1066338).

Almost surely, 2^21210075 is an apocalyptic number.

21210075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21210075 is a deficient number, since it is larger than the sum of its proper divisors (17178093).

21210075 is a wasteful number, since it uses less digits than its factorization.

21210075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1004 (or 996 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21210075 is about 4605.4397184199. The cubic root of 21210075 is about 276.8093367481.

Adding to 21210075 its reverse (57001212), we get a palindrome (78211287).

The spelling of 21210075 in words is "twenty-one million, two hundred ten thousand, seventy-five".