21231266 has 32 divisors (see below), whose sum is σ = 39595392. Its totient is φ = 8328960.

The previous prime is 21231253. The next prime is 21231269. The reversal of 21231266 is 66213212.

It is not an unprimeable number, because it can be changed into a prime (21231269) 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 15 ways as a sum of consecutive naturals, for example, 7601 + ... + 10011.

It is an arithmetic number, because the mean of its divisors is an integer number (1237356).

Almost surely, 2^21231266 is an apocalyptic number.

21231266 is a deficient number, since it is larger than the sum of its proper divisors (18364126).

21231266 is a wasteful number, since it uses less digits than its factorization.

21231266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2474.

The product of its digits is 864, while the sum is 23.

The square root of 21231266 is about 4607.7397930005. The cubic root of 21231266 is about 276.9014928611.

Adding to 21231266 its reverse (66213212), we get a palindrome (87444478).

The spelling of 21231266 in words is "twenty-one million, two hundred thirty-one thousand, two hundred sixty-six".