243214021 has 4 divisors (see below), whose sum is σ = 244258092. Its totient is φ = 242169952.

The previous prime is 243213991. The next prime is 243214043. The reversal of 243214021 is 120412342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120412342 = 2 ⋅60206171.

It can be written as a sum of positive squares in 2 ways, for example, as 160149025 + 83064996 = 12655^2 + 9114^2 .

It is a cyclic number.

It is not a de Polignac number, because 243214021 - 2¹³ = 243205829 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 243214021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243214051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 521686 + ... + 522151.

It is an arithmetic number, because the mean of its divisors is an integer number (61064523).

Almost surely, 2^243214021 is an apocalyptic number.

It is an amenable number.

243214021 is a deficient number, since it is larger than the sum of its proper divisors (1044071).

243214021 is a wasteful number, since it uses less digits than its factorization.

243214021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044070.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 243214021 is about 15595.3204840426. The cubic root of 243214021 is about 624.2082954698.

Adding to 243214021 its reverse (120412342), we get a palindrome (363626363).

The spelling of 243214021 in words is "two hundred forty-three million, two hundred fourteen thousand, twenty-one".