242545021 has 4 divisors (see below), whose sum is σ = 243776412. Its totient is φ = 241313632.

The previous prime is 242544989. The next prime is 242545033. The reversal of 242545021 is 120545242.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120545242 = 2 ⋅60272621.

It can be written as a sum of positive squares in 2 ways, for example, as 107868996 + 134676025 = 10386^2 + 11605^2 .

It is a cyclic number.

It is not a de Polignac number, because 242545021 - 2⁵ = 242544989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (242545421) 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, 615400 + ... + 615793.

It is an arithmetic number, because the mean of its divisors is an integer number (60944103).

Almost surely, 2^242545021 is an apocalyptic number.

It is an amenable number.

242545021 is a deficient number, since it is larger than the sum of its proper divisors (1231391).

242545021 is a wasteful number, since it uses less digits than its factorization.

242545021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1231390.

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 242545021 is about 15573.8569725036. The cubic root of 242545021 is about 623.6354408535.

The spelling of 242545021 in words is "two hundred forty-two million, five hundred forty-five thousand, twenty-one".