21231153 has 24 divisors (see below), whose sum is σ = 32594016. Its totient is φ = 13802400.

The previous prime is 21231143. The next prime is 21231173. The reversal of 21231153 is 35113212.

It is not a de Polignac number, because 21231153 - 2⁸ = 21230897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21231143) 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 23 ways as a sum of consecutive naturals, for example, 8898 + ... + 11028.

It is an arithmetic number, because the mean of its divisors is an integer number (1358084).

Almost surely, 2^21231153 is an apocalyptic number.

It is an amenable number.

21231153 is a deficient number, since it is larger than the sum of its proper divisors (11362863).

21231153 is an equidigital number, since it uses as much as digits as its factorization.

21231153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2187 (or 2175 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21231153 is about 4607.7275310070. The cubic root of 21231153 is about 276.9010016057.

Adding to 21231153 its reverse (35113212), we get a palindrome (56344365).

The spelling of 21231153 in words is "twenty-one million, two hundred thirty-one thousand, one hundred fifty-three".