21234171 has 16 divisors (see below), whose sum is σ = 32674304. Its totient is φ = 12014784.

The previous prime is 21234151. The next prime is 21234203. The reversal of 21234171 is 17143212.

It is a de Polignac number, because none of the positive numbers 2^k-21234171 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21234151) 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, 2746 + ... + 7071.

It is an arithmetic number, because the mean of its divisors is an integer number (2042144).

Almost surely, 2^21234171 is an apocalyptic number.

21234171 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21234171 is a deficient number, since it is larger than the sum of its proper divisors (11440133).

21234171 is a wasteful number, since it uses less digits than its factorization.

21234171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9930.

The product of its digits is 336, while the sum is 21.

The square root of 21234171 is about 4608.0550126924. The cubic root of 21234171 is about 276.9141214400.

Adding to 21234171 its reverse (17143212), we get a palindrome (38377383).

The spelling of 21234171 in words is "twenty-one million, two hundred thirty-four thousand, one hundred seventy-one".