21231255 has 16 divisors (see below), whose sum is σ = 34040160. Its totient is φ = 11299968.

The previous prime is 21231253. The next prime is 21231269. The reversal of 21231255 is 55213212.

It is not a de Polignac number, because 21231255 - 2¹ = 21231253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231253) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8041 + ... + 10349.

It is an arithmetic number, because the mean of its divisors is an integer number (2127510).

Almost surely, 2^21231255 is an apocalyptic number.

21231255 is a deficient number, since it is larger than the sum of its proper divisors (12808905).

21231255 is a wasteful number, since it uses less digits than its factorization.

21231255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2930.

The product of its digits is 600, while the sum is 21.

The square root of 21231255 is about 4607.7385993565. The cubic root of 21231255 is about 276.9014450398.

Adding to 21231255 its reverse (55213212), we get a palindrome (76444467).

The spelling of 21231255 in words is "twenty-one million, two hundred thirty-one thousand, two hundred fifty-five".