21411231 has 4 divisors (see below), whose sum is σ = 28548312. Its totient is φ = 14274152.

The previous prime is 21411223. The next prime is 21411239. The reversal of 21411231 is 13211412.

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

It is an interprime number because it is at equal distance from previous prime (21411223) and next prime (21411239).

It is a cyclic number.

It is not a de Polignac number, because 21411231 - 2³ = 21411223 is a prime.

It is a super-2 number, since 2×21411231² = 916881625870722, which contains 22 as substring.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 21411231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21411239) 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, 3568536 + ... + 3568541.

It is an arithmetic number, because the mean of its divisors is an integer number (7137078).

Almost surely, 2^21411231 is an apocalyptic number.

21411231 is a deficient number, since it is larger than the sum of its proper divisors (7137081).

21411231 is an equidigital number, since it uses as much as digits as its factorization.

21411231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7137080.

The product of its digits is 48, while the sum is 15.

The square root of 21411231 is about 4627.2271394432. The cubic root of 21411231 is about 277.6816698568.

Adding to 21411231 its reverse (13211412), we get a palindrome (34622643).

The spelling of 21411231 in words is "twenty-one million, four hundred eleven thousand, two hundred thirty-one".