1388666212209 has 24 divisors (see below), whose sum is σ = 2125622975112. Its totient is φ = 870589501440.

The previous prime is 1388666212207. The next prime is 1388666212217. The reversal of 1388666212209 is 9022126668831.

It can be written as a sum of positive squares in 4 ways, for example, as 132816513600 + 1255849698609 = 364440^2 + 1120647^2 .

It is not a de Polignac number, because 1388666212209 - 2¹ = 1388666212207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1388666212207) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3621432 + ... + 3986489.

It is an arithmetic number, because the mean of its divisors is an integer number (88567623963).

Almost surely, 2^{1388666212209} is an apocalyptic number.

It is an amenable number.

1388666212209 is a deficient number, since it is larger than the sum of its proper divisors (736956762903).

1388666212209 is a wasteful number, since it uses less digits than its factorization.

1388666212209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7609137 (or 7609134 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The spelling of 1388666212209 in words is "one trillion, three hundred eighty-eight billion, six hundred sixty-six million, two hundred twelve thousand, two hundred nine".