21110231 has 4 divisors (see below), whose sum is σ = 21838200. Its totient is φ = 20382264.

The previous prime is 21110227. The next prime is 21110233. The reversal of 21110231 is 13201112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21110231 - 2² = 21110227 is a prime.

It is a super-2 number, since 2×21110231² = 891283705746722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110233) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 363941 + ... + 363998.

It is an arithmetic number, because the mean of its divisors is an integer number (5459550).

Almost surely, 2^21110231 is an apocalyptic number.

21110231 is a deficient number, since it is larger than the sum of its proper divisors (727969).

21110231 is an equidigital number, since it uses as much as digits as its factorization.

21110231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727968.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21110231 is about 4594.5871414089. The cubic root of 21110231 is about 276.3743039885.

Adding to 21110231 its reverse (13201112), we get a palindrome (34311343).

The spelling of 21110231 in words is "twenty-one million, one hundred ten thousand, two hundred thirty-one".