21340001 has 4 divisors (see below), whose sum is σ = 21373632. Its totient is φ = 21306372.

The previous prime is 21339991. The next prime is 21340003. The reversal of 21340001 is 10004312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21340001 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21340003) 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, 15845 + ... + 17138.

It is an arithmetic number, because the mean of its divisors is an integer number (5343408).

Almost surely, 2^21340001 is an apocalyptic number.

It is an amenable number.

21340001 is a deficient number, since it is larger than the sum of its proper divisors (33631).

21340001 is an equidigital number, since it uses as much as digits as its factorization.

21340001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33630.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21340001 is about 4619.5238932167. The cubic root of 21340001 is about 277.3734011171.

Adding to 21340001 its reverse (10004312), we get a palindrome (31344313).

The spelling of 21340001 in words is "twenty-one million, three hundred forty thousand, one".