21142241 has 4 divisors (see below), whose sum is σ = 21272112. Its totient is φ = 21012372.

The previous prime is 21142223. The next prime is 21142243. The reversal of 21142241 is 14224112.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21142241 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21142243) 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, 64691 + ... + 65016.

It is an arithmetic number, because the mean of its divisors is an integer number (5318028).

Almost surely, 2^21142241 is an apocalyptic number.

It is an amenable number.

21142241 is a deficient number, since it is larger than the sum of its proper divisors (129871).

21142241 is a wasteful number, since it uses less digits than its factorization.

21142241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129870.

The product of its digits is 128, while the sum is 17.

The square root of 21142241 is about 4598.0692687257. The cubic root of 21142241 is about 276.5139246574.

Adding to 21142241 its reverse (14224112), we get a palindrome (35366353).

The spelling of 21142241 in words is "twenty-one million, one hundred forty-two thousand, two hundred forty-one".