21340267 has 4 divisors (see below), whose sum is σ = 22981840. Its totient is φ = 19698696.

The previous prime is 21340247. The next prime is 21340273. The reversal of 21340267 is 76204312.

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 21340267 - 2¹⁹ = 20815979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21340217) 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 3 ways as a sum of consecutive naturals, for example, 820767 + ... + 820792.

It is an arithmetic number, because the mean of its divisors is an integer number (5745460).

Almost surely, 2^21340267 is an apocalyptic number.

21340267 is a deficient number, since it is larger than the sum of its proper divisors (1641573).

21340267 is a wasteful number, since it uses less digits than its factorization.

21340267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1641572.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21340267 is about 4619.5526839728. The cubic root of 21340267 is about 277.3745535853.

Adding to 21340267 its reverse (76204312), we get a palindrome (97544579).

The spelling of 21340267 in words is "twenty-one million, three hundred forty thousand, two hundred sixty-seven".