1388458665 has 120 divisors (see below), whose sum is σ = 2833011720. Its totient is φ = 649313280.

The previous prime is 1388458627. The next prime is 1388458693. The reversal of 1388458665 is 5668548831.

It can be written as a sum of positive squares in 4 ways, for example, as 440496144 + 947962521 = 20988^2 + 30789^2 .

It is not a de Polignac number, because 1388458665 - 2⁶ = 1388458601 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 1420657 + ... + 1421633.

It is an arithmetic number, because the mean of its divisors is an integer number (23608431).

Almost surely, 2^1388458665 is an apocalyptic number.

1388458665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1388458665 is an abundant number, since it is smaller than the sum of its proper divisors (1444553055).

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

1388458665 is a wasteful number, since it uses less digits than its factorization.

1388458665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1045 (or 1025 counting only the distinct ones).

The product of its digits is 5529600, while the sum is 54.

The square root of 1388458665 is about 37262.0271187707. The cubic root of 1388458665 is about 1115.6063691543.

The spelling of 1388458665 in words is "one billion, three hundred eighty-eight million, four hundred fifty-eight thousand, six hundred sixty-five".