1385531666 has 8 divisors (see below), whose sum is σ = 2149963020. Its totient is φ = 668877328.

The previous prime is 1385531657. The next prime is 1385531687. The reversal of 1385531666 is 6661355831.

It can be written as a sum of positive squares in 2 ways, for example, as 1359470641 + 26061025 = 36871^2 + 5105^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-5 number, since 5×1385531666⁵ (a number of 47 digits) contains 55555 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11944181 + ... + 11944296.

Almost surely, 2^1385531666 is an apocalyptic number.

1385531666 is a deficient number, since it is larger than the sum of its proper divisors (764431354).

1385531666 is a wasteful number, since it uses less digits than its factorization.

1385531666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23888508.

The product of its digits is 388800, while the sum is 44.

The square root of 1385531666 is about 37222.7305016706. The cubic root of 1385531666 is about 1114.8218839133.

The spelling of 1385531666 in words is "one billion, three hundred eighty-five million, five hundred thirty-one thousand, six hundred sixty-six".