21942241 has 4 divisors (see below), whose sum is σ = 22698900. Its totient is φ = 21185584.

The previous prime is 21942209. The next prime is 21942251. The reversal of 21942241 is 14224912.

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 7311616 + 14630625 = 2704^2 + 3825^2 .

It is a cyclic number.

It is not a de Polignac number, because 21942241 - 2⁵ = 21942209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21942251) 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, 378286 + ... + 378343.

It is an arithmetic number, because the mean of its divisors is an integer number (5674725).

Almost surely, 2^21942241 is an apocalyptic number.

It is an amenable number.

21942241 is a deficient number, since it is larger than the sum of its proper divisors (756659).

21942241 is an equidigital number, since it uses as much as digits as its factorization.

21942241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 756658.

The product of its digits is 1152, while the sum is 25.

The square root of 21942241 is about 4684.2545831754. The cubic root of 21942241 is about 279.9585015029.

The spelling of 21942241 in words is "twenty-one million, nine hundred forty-two thousand, two hundred forty-one".