21634231 has 4 divisors (see below), whose sum is σ = 21648600. Its totient is φ = 21619864.

The previous prime is 21634213. The next prime is 21634253. The reversal of 21634231 is 13243612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21634231 - 2⁹ = 21633719 is a prime.

It is a super-2 number, since 2×21634231² = 936079901922722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21634271) 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 3 ways as a sum of consecutive naturals, for example, 4621 + ... + 8038.

It is an arithmetic number, because the mean of its divisors is an integer number (5412150).

Almost surely, 2^21634231 is an apocalyptic number.

21634231 is a deficient number, since it is larger than the sum of its proper divisors (14369).

21634231 is a wasteful number, since it uses less digits than its factorization.

21634231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14368.

The product of its digits is 864, while the sum is 22.

The square root of 21634231 is about 4651.2612268072. The cubic root of 21634231 is about 278.6423692469.

Adding to 21634231 its reverse (13243612), we get a palindrome (34877843).

The spelling of 21634231 in words is "twenty-one million, six hundred thirty-four thousand, two hundred thirty-one".