21044869 has 4 divisors (see below), whose sum is σ = 21441996. Its totient is φ = 20647744.

The previous prime is 21044833. The next prime is 21044873. The reversal of 21044869 is 96844012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16507969 + 4536900 = 4063^2 + 2130^2 .

It is a cyclic number.

It is not a de Polignac number, because 21044869 - 2²¹ = 18947717 is a prime.

It is a super-2 number, since 2×21044869² = 885773022454322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044879) 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, 198484 + ... + 198589.

It is an arithmetic number, because the mean of its divisors is an integer number (5360499).

Almost surely, 2^21044869 is an apocalyptic number.

It is an amenable number.

21044869 is a deficient number, since it is larger than the sum of its proper divisors (397127).

21044869 is an equidigital number, since it uses as much as digits as its factorization.

21044869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397126.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 21044869 is about 4587.4686919913. The cubic root of 21044869 is about 276.0887701924.

The spelling of 21044869 in words is "twenty-one million, forty-four thousand, eight hundred sixty-nine".