21125211 has 8 divisors (see below), whose sum is σ = 28189200. Its totient is φ = 14072352.

The previous prime is 21125183. The next prime is 21125219. The reversal of 21125211 is 11252112.

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

It is not a de Polignac number, because 21125211 - 2⁹ = 21124699 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21125219) 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, 4041 + ... + 7653.

It is an arithmetic number, because the mean of its divisors is an integer number (3523650).

Almost surely, 2^21125211 is an apocalyptic number.

21125211 is a deficient number, since it is larger than the sum of its proper divisors (7063989).

21125211 is a wasteful number, since it uses less digits than its factorization.

21125211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5565.

The product of its digits is 40, while the sum is 15.

The square root of 21125211 is about 4596.2170314292. The cubic root of 21125211 is about 276.4396610529.

Adding to 21125211 its reverse (11252112), we get a palindrome (32377323).

The spelling of 21125211 in words is "twenty-one million, one hundred twenty-five thousand, two hundred eleven".