242540021 has 8 divisors (see below), whose sum is σ = 251245920. Its totient is φ = 233857008.

The previous prime is 242540009. The next prime is 242540057. The reversal of 242540021 is 120045242.

242540021 = T₃₅₈ + T₃₅₉ + ... + T₁₁₄₄.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 242540021 - 2¹⁰ = 242538997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 242539975 and 242540002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (242540521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17510 + ... + 28136.

It is an arithmetic number, because the mean of its divisors is an integer number (31405740).

Almost surely, 2^242540021 is an apocalyptic number.

It is an amenable number.

242540021 is a deficient number, since it is larger than the sum of its proper divisors (8705899).

242540021 is a wasteful number, since it uses less digits than its factorization.

242540021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11443.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 242540021 is about 15573.6964462519. The cubic root of 242540021 is about 623.6311554654.

Adding to 242540021 its reverse (120045242), we get a palindrome (362585263).

The spelling of 242540021 in words is "two hundred forty-two million, five hundred forty thousand, twenty-one".