21431135 has 16 divisors (see below), whose sum is σ = 29706912. Its totient is φ = 14668800.

The previous prime is 21431131. The next prime is 21431141. The reversal of 21431135 is 53113412.

It is not a de Polignac number, because 21431135 - 2² = 21431131 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431131) 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, 10526 + ... + 12395.

It is an arithmetic number, because the mean of its divisors is an integer number (1856682).

Almost surely, 2^21431135 is an apocalyptic number.

21431135 is a deficient number, since it is larger than the sum of its proper divisors (8275777).

21431135 is a wasteful number, since it uses less digits than its factorization.

21431135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22954.

The product of its digits is 360, while the sum is 20.

The square root of 21431135 is about 4629.3773879432. The cubic root of 21431135 is about 277.7676880187.

Adding to 21431135 its reverse (53113412), we get a palindrome (74544547).

The spelling of 21431135 in words is "twenty-one million, four hundred thirty-one thousand, one hundred thirty-five".