21242141 has 4 divisors (see below), whose sum is σ = 21760284. Its totient is φ = 20724000.

The previous prime is 21242131. The next prime is 21242153. The reversal of 21242141 is 14124212.

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 2493241 + 18748900 = 1579^2 + 4330^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242141 - 2⁶ = 21242077 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242101) 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, 259010 + ... + 259091.

It is an arithmetic number, because the mean of its divisors is an integer number (5440071).

Almost surely, 2^21242141 is an apocalyptic number.

It is an amenable number.

21242141 is a deficient number, since it is larger than the sum of its proper divisors (518143).

21242141 is an equidigital number, since it uses as much as digits as its factorization.

21242141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 518142.

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

The square root of 21242141 is about 4608.9197215834. The cubic root of 21242141 is about 276.9487626084.

Adding to 21242141 its reverse (14124212), we get a palindrome (35366353).

The spelling of 21242141 in words is "twenty-one million, two hundred forty-two thousand, one hundred forty-one".