242921 has 4 divisors (see below), whose sum is σ = 277632. Its totient is φ = 208212.

The previous prime is 242911. The next prime is 242923. The reversal of 242921 is 129242.

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, and also an emirpimes, since its reverse is a distinct semiprime: 129242 = 2 ⋅64621.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-242921 is a prime.

It is a super-2 number, since 2×242921² = 118021224482, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 242893 and 242902.

It is not an unprimeable number, because it can be changed into a prime (242923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17345 + ... + 17358.

It is an arithmetic number, because the mean of its divisors is an integer number (69408).

2²⁴²⁹²¹ is an apocalyptic number.

It is an amenable number.

242921 is a deficient number, since it is larger than the sum of its proper divisors (34711).

242921 is an equidigital number, since it uses as much as digits as its factorization.

242921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34710.

The product of its digits is 288, while the sum is 20.

The square root of 242921 is about 492.8701654594. The cubic root of 242921 is about 62.3957515462.

The spelling of 242921 in words is "two hundred forty-two thousand, nine hundred twenty-one".