243921001 has 4 divisors (see below), whose sum is σ = 252332100. Its totient is φ = 235509904.

The previous prime is 243920977. The next prime is 243921011. The reversal of 243921001 is 100129342.

243921001 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 100129342 = 2 ⋅50064671.

It can be written as a sum of positive squares in 2 ways, for example, as 116208400 + 127712601 = 10780^2 + 11301^2 .

It is a cyclic number.

It is not a de Polignac number, because 243921001 - 2⁹ = 243920489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243921011) 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, 4205506 + ... + 4205563.

It is an arithmetic number, because the mean of its divisors is an integer number (63083025).

Almost surely, 2^243921001 is an apocalyptic number.

It is an amenable number.

243921001 is a deficient number, since it is larger than the sum of its proper divisors (8411099).

243921001 is an equidigital number, since it uses as much as digits as its factorization.

243921001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8411098.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 243921001 is about 15617.9704507340. The cubic root of 243921001 is about 624.8125312944.

The spelling of 243921001 in words is "two hundred forty-three million, nine hundred twenty-one thousand, one".