1389555666 has 12 divisors (see below), whose sum is σ = 3010703982. Its totient is φ = 463185216.

The previous prime is 1389555659. The next prime is 1389555667. The reversal of 1389555666 is 6665559831.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1281998025 + 107557641 = 35805^2 + 10371^2 .

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1389555667) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 38598751 + ... + 38598786.

Almost surely, 2^1389555666 is an apocalyptic number.

1389555666 is an abundant number, since it is smaller than the sum of its proper divisors (1621148316).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1389555666 is a wasteful number, since it uses less digits than its factorization.

1389555666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77197545 (or 77197542 counting only the distinct ones).

The product of its digits is 5832000, while the sum is 54.

The square root of 1389555666 is about 37276.7443052636. The cubic root of 1389555666 is about 1115.9000999334.

The spelling of 1389555666 in words is "one billion, three hundred eighty-nine million, five hundred fifty-five thousand, six hundred sixty-six".