21231105 has 16 divisors (see below), whose sum is σ = 38822784. Its totient is φ = 9705600.

The previous prime is 21231029. The next prime is 21231107. The reversal of 21231105 is 50113212.

It is not a de Polignac number, because 21231105 - 2¹³ = 21222913 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (21231107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100996 + ... + 101205.

It is an arithmetic number, because the mean of its divisors is an integer number (2426424).

Almost surely, 2^21231105 is an apocalyptic number.

It is an amenable number.

21231105 is a deficient number, since it is larger than the sum of its proper divisors (17591679).

21231105 is a wasteful number, since it uses less digits than its factorization.

21231105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202216.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21231105 is about 4607.7223223628. The cubic root of 21231105 is about 276.9007929303.

Adding to 21231105 its reverse (50113212), we get a palindrome (71344317).

The spelling of 21231105 in words is "twenty-one million, two hundred thirty-one thousand, one hundred five".