21707841 has 4 divisors (see below), whose sum is σ = 28943792. Its totient is φ = 14471892.

The previous prime is 21707797. The next prime is 21707849. The reversal of 21707841 is 14870712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21707841 - 2⁷ = 21707713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21707799 and 21707808.

It is not an unprimeable number, because it can be changed into a prime (21707849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3617971 + ... + 3617976.

It is an arithmetic number, because the mean of its divisors is an integer number (7235948).

Almost surely, 2^21707841 is an apocalyptic number.

It is an amenable number.

21707841 is a deficient number, since it is larger than the sum of its proper divisors (7235951).

21707841 is an equidigital number, since it uses as much as digits as its factorization.

21707841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7235950.

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 21707841 is about 4659.1674148929. The cubic root of 21707841 is about 278.9580363654.

It can be divided in two parts, 2170 and 7841, that added together give a triangular number (10011 = T₁₄₁).

The spelling of 21707841 in words is "twenty-one million, seven hundred seven thousand, eight hundred forty-one".