243752021 has 2 divisors, whose sum is σ = 243752022. Its totient is φ = 243752020.

The previous prime is 243751987. The next prime is 243752023. The reversal of 243752021 is 120257342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 243048100 + 703921 = 15590^2 + 839^2 .

It is a cyclic number.

It is not a de Polignac number, because 243752021 - 2⁶ = 243751957 is a prime.

Together with 243752023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243752023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121876010 + 121876011.

It is an arithmetic number, because the mean of its divisors is an integer number (121876011).

Almost surely, 2^243752021 is an apocalyptic number.

It is an amenable number.

243752021 is a deficient number, since it is larger than the sum of its proper divisors (1).

243752021 is an equidigital number, since it uses as much as digits as its factorization.

243752021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 243752021 is about 15612.5597196616. The cubic root of 243752021 is about 624.6682151546.

The spelling of 243752021 in words is "two hundred forty-three million, seven hundred fifty-two thousand, twenty-one".