242728921 has 2 divisors, whose sum is σ = 242728922. Its totient is φ = 242728920.

The previous prime is 242728919. The next prime is 242728963. The reversal of 242728921 is 129827242.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 239042521 + 3686400 = 15461^2 + 1920^2 .

It is a cyclic number.

It is not a de Polignac number, because 242728921 - 2¹ = 242728919 is a prime.

Together with 242728919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (242720921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121364460 + 121364461.

It is an arithmetic number, because the mean of its divisors is an integer number (121364461).

Almost surely, 2^242728921 is an apocalyptic number.

It is an amenable number.

242728921 is a deficient number, since it is larger than the sum of its proper divisors (1).

242728921 is an equidigital number, since it uses as much as digits as its factorization.

242728921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 37.

The square root of 242728921 is about 15579.7599788957. The cubic root of 242728921 is about 623.7930165259.

The spelling of 242728921 in words is "two hundred forty-two million, seven hundred twenty-eight thousand, nine hundred twenty-one".