242040021 has 4 divisors (see below), whose sum is σ = 322720032. Its totient is φ = 161360012.

The previous prime is 242039969. The next prime is 242040023. The reversal of 242040021 is 120040242.

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 not a de Polignac number, because 242040021 - 2⁹ = 242039509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (242040023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40340001 + ... + 40340006.

It is an arithmetic number, because the mean of its divisors is an integer number (80680008).

Almost surely, 2^242040021 is an apocalyptic number.

It is an amenable number.

242040021 is a deficient number, since it is larger than the sum of its proper divisors (80680011).

242040021 is an equidigital number, since it uses as much as digits as its factorization.

242040021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80680010.

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 242040021 is about 15557.6354565853. The cubic root of 242040021 is about 623.2023188923.

Adding to 242040021 its reverse (120040242), we get a palindrome (362080263).

The spelling of 242040021 in words is "two hundred forty-two million, forty thousand, twenty-one".