21102231 has 4 divisors (see below), whose sum is σ = 28136312. Its totient is φ = 14068152.

The previous prime is 21102209. The next prime is 21102239. The reversal of 21102231 is 13220112.

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

It is not a de Polignac number, because 21102231 - 2⁵ = 21102199 is a prime.

It is a super-3 number, since 3×21102231³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102239) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3517036 + ... + 3517041.

It is an arithmetic number, because the mean of its divisors is an integer number (7034078).

Almost surely, 2^21102231 is an apocalyptic number.

21102231 is a deficient number, since it is larger than the sum of its proper divisors (7034081).

21102231 is an equidigital number, since it uses as much as digits as its factorization.

21102231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7034080.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21102231 is about 4593.7164692654. The cubic root of 21102231 is about 276.3393876836.

Adding to 21102231 its reverse (13220112), we get a palindrome (34322343).

The spelling of 21102231 in words is "twenty-one million, one hundred two thousand, two hundred thirty-one".