21300043 has 4 divisors (see below), whose sum is σ = 21341448. Its totient is φ = 21258640.

The previous prime is 21300029. The next prime is 21300061. The reversal of 21300043 is 34000312.

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 21300043 - 2¹⁷ = 21168971 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21299996 and 21300032.

It is not an unprimeable number, because it can be changed into a prime (21300143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19921 + ... + 20962.

It is an arithmetic number, because the mean of its divisors is an integer number (5335362).

Almost surely, 2^21300043 is an apocalyptic number.

21300043 is a deficient number, since it is larger than the sum of its proper divisors (41405).

21300043 is an equidigital number, since it uses as much as digits as its factorization.

21300043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41404.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21300043 is about 4615.1969622108. The cubic root of 21300043 is about 277.2001707100.

Adding to 21300043 its reverse (34000312), we get a palindrome (55300355).

The spelling of 21300043 in words is "twenty-one million, three hundred thousand, forty-three".