21100243 has 8 divisors (see below), whose sum is σ = 22108160. Its totient is φ = 20112840.

The previous prime is 21100231. The next prime is 21100253. The reversal of 21100243 is 34200112.

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 21100243 - 2¹³ = 21092051 is a prime.

It is the 4594-th Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100253) by changing a digit.

It is a nontrivial repunit in base 4593.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3003 + ... + 7156.

It is an arithmetic number, because the mean of its divisors is an integer number (2763520).

Almost surely, 2^21100243 is an apocalyptic number.

21100243 is a deficient number, since it is larger than the sum of its proper divisors (1007917).

21100243 is a wasteful number, since it uses less digits than its factorization.

21100243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10257.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21100243 is about 4593.5000816371. The cubic root of 21100243 is about 276.3307096129.

Adding to 21100243 its reverse (34200112), we get a palindrome (55300355).

The spelling of 21100243 in words is "twenty-one million, one hundred thousand, two hundred forty-three".