21056041 has 4 divisors (see below), whose sum is σ = 21401284. Its totient is φ = 20710800.

The previous prime is 21056039. The next prime is 21056051. The reversal of 21056041 is 14065012.

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 3916441 + 17139600 = 1979^2 + 4140^2 .

It is a cyclic number.

It is not a de Polignac number, because 21056041 - 2¹ = 21056039 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21056011) 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, 172530 + ... + 172651.

It is an arithmetic number, because the mean of its divisors is an integer number (5350321).

Almost surely, 2^21056041 is an apocalyptic number.

It is an amenable number.

21056041 is a deficient number, since it is larger than the sum of its proper divisors (345243).

21056041 is an equidigital number, since it uses as much as digits as its factorization.

21056041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345242.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21056041 is about 4588.6861954159. The cubic root of 21056041 is about 276.1376169064.

The spelling of 21056041 in words is "twenty-one million, fifty-six thousand, forty-one".