21297843 has 16 divisors (see below), whose sum is σ = 36060160. Its totient is φ = 12170088.

The previous prime is 21297817. The next prime is 21297851. The reversal of 21297843 is 34879212.

It is not a de Polignac number, because 21297843 - 2⁵ = 21297811 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21297798 and 21297807.

It is not an unprimeable number, because it can be changed into a prime (21297853) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56155 + ... + 56532.

It is an arithmetic number, because the mean of its divisors is an integer number (2253760).

Almost surely, 2^21297843 is an apocalyptic number.

21297843 is a deficient number, since it is larger than the sum of its proper divisors (14762317).

21297843 is a wasteful number, since it uses less digits than its factorization.

21297843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112703 (or 112697 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21297843 is about 4614.9586130322. The cubic root of 21297843 is about 277.1906267328.

The spelling of 21297843 in words is "twenty-one million, two hundred ninety-seven thousand, eight hundred forty-three".