242521021 has 2 divisors, whose sum is σ = 242521022. Its totient is φ = 242521020.

The previous prime is 242521009. The next prime is 242521061. The reversal of 242521021 is 120125242.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 235284921 + 7236100 = 15339^2 + 2690^2 .

It is a cyclic number.

It is not a de Polignac number, because 242521021 - 2²³ = 234132413 is a prime.

It is a super-3 number, since 3×242521021³ (a number of 26 digits) contains 333 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 242521021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (242521001) 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 as a sum of consecutive naturals, namely, 121260510 + 121260511.

It is an arithmetic number, because the mean of its divisors is an integer number (121260511).

Almost surely, 2^242521021 is an apocalyptic number.

It is an amenable number.

242521021 is a deficient number, since it is larger than the sum of its proper divisors (1).

242521021 is an equidigital number, since it uses as much as digits as its factorization.

242521021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 242521021 is about 15573.0864314047. The cubic root of 242521021 is about 623.6148704535.

Adding to 242521021 its reverse (120125242), we get a palindrome (362646263).

The spelling of 242521021 in words is "two hundred forty-two million, five hundred twenty-one thousand, twenty-one".