243209997 has 6 divisors (see below), whose sum is σ = 351303342. Its totient is φ = 162139992.

The previous prime is 243209983. The next prime is 243210001. The reversal of 243209997 is 799902342.

It can be written as a sum of positive squares in only one way, i.e., 230614596 + 12595401 = 15186^2 + 3549^2 .

It is not a de Polignac number, because 243209997 - 2²⁴ = 226432781 is a prime.

It is a super-2 number, since 2×243209997² = 118302205281480018, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243209927) 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 5 ways as a sum of consecutive naturals, for example, 13511658 + ... + 13511675.

It is an arithmetic number, because the mean of its divisors is an integer number (58550557).

Almost surely, 2^243209997 is an apocalyptic number.

It is an amenable number.

243209997 is a deficient number, since it is larger than the sum of its proper divisors (108093345).

243209997 is a wasteful number, since it uses less digits than its factorization.

243209997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27023339 (or 27023336 counting only the distinct ones).

The product of its (nonzero) digits is 244944, while the sum is 45.

The square root of 243209997 is about 15595.1914704501. The cubic root of 243209997 is about 624.2048529215.

The spelling of 243209997 in words is "two hundred forty-three million, two hundred nine thousand, nine hundred ninety-seven".