1243434205665 has 12 divisors (see below), whose sum is σ = 2155285956564. Its totient is φ = 663164909664.

The previous prime is 1243434205661. The next prime is 1243434205703. The reversal of 1243434205665 is 5665024343421.

1243434205665 is a `hidden beast` number, since 1 + 2 + 4 + 3 + 43 + 42 + 0 + 566 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 562428002304 + 681006203361 = 749952^2 + 825231^2 .

It is not a de Polignac number, because 1243434205665 - 2² = 1243434205661 is a prime.

It is a super-2 number, since 2×1243434205665² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 27631871237 = 1243434205665 / (1 + 2 + 4 + 3 + 4 + 3 + 4 + 2 + 0 + 5 + 6 + 6 + 5).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1243434205665.

It is not an unprimeable number, because it can be changed into a prime (1243434205661) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13815935574 + ... + 13815935663.

It is an arithmetic number, because the mean of its divisors is an integer number (179607163047).

Almost surely, 2^{1243434205665} is an apocalyptic number.

1243434205665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1243434205665 is a deficient number, since it is larger than the sum of its proper divisors (911851750899).

1243434205665 is a wasteful number, since it uses less digits than its factorization.

1243434205665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27631871248 (or 27631871245 counting only the distinct ones).

The product of its (nonzero) digits is 2073600, while the sum is 45.

The spelling of 1243434205665 in words is "one trillion, two hundred forty-three billion, four hundred thirty-four million, two hundred five thousand, six hundred sixty-five".