21340231 has 8 divisors (see below), whose sum is σ = 23909904. Its totient is φ = 18875520.

The previous prime is 21340223. The next prime is 21340243. The reversal of 21340231 is 13204312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21340231 - 2³ = 21340223 is a prime.

It is a super-2 number, since 2×21340231² = 910810918266722, 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 (21340931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25810 + ... + 26623.

It is an arithmetic number, because the mean of its divisors is an integer number (2988738).

Almost surely, 2^21340231 is an apocalyptic number.

21340231 is a deficient number, since it is larger than the sum of its proper divisors (2569673).

21340231 is a wasteful number, since it uses less digits than its factorization.

21340231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52481.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21340231 is about 4619.5487874900. The cubic root of 21340231 is about 277.3743976127.

Adding to 21340231 its reverse (13204312), we get a palindrome (34544543).

The spelling of 21340231 in words is "twenty-one million, three hundred forty thousand, two hundred thirty-one".