21169243 has 4 divisors (see below), whose sum is σ = 21685608. Its totient is φ = 20652880.

The previous prime is 21169241. The next prime is 21169261. The reversal of 21169243 is 34296112.

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 21169243 - 2¹ = 21169241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21169241) 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, 258121 + ... + 258202.

It is an arithmetic number, because the mean of its divisors is an integer number (5421402).

Almost surely, 2^21169243 is an apocalyptic number.

21169243 is a deficient number, since it is larger than the sum of its proper divisors (516365).

21169243 is an equidigital number, since it uses as much as digits as its factorization.

21169243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516364.

The product of its digits is 2592, while the sum is 28.

The square root of 21169243 is about 4601.0045642229. The cubic root of 21169243 is about 276.6315919794.

It can be divided in two parts, 21169 and 243, that added together give a palindrome (21412).

The spelling of 21169243 in words is "twenty-one million, one hundred sixty-nine thousand, two hundred forty-three".