1386217728 has 432 divisors, whose sum is σ = 4943667456. Its totient is φ = 364953600.

The previous prime is 1386217727. The next prime is 1386217733. The reversal of 1386217728 is 8277126831.

1386217728 is a `hidden beast` number, since 13 + 8 + 621 + 7 + 7 + 2 + 8 = 666.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (1386217727) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13724878 + ... + 13724978.

Almost surely, 2^1386217728 is an apocalyptic number.

1386217728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1386217728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2471833728).

1386217728 is an abundant number, since it is smaller than the sum of its proper divisors (3557449728).

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

1386217728 is a wasteful number, since it uses less digits than its factorization.

1386217728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 173 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The square root of 1386217728 is about 37231.9449935133. The cubic root of 1386217728 is about 1115.0058591929.

It can be divided in two parts, 1386217 and 728, that added together give a triangular number (1386945 = T₁₆₆₅).

The spelling of 1386217728 in words is "one billion, three hundred eighty-six million, two hundred seventeen thousand, seven hundred twenty-eight".