1388731428 has 144 divisors (see below), whose sum is σ = 4385332224. Its totient is φ = 361359360.

The previous prime is 1388731427. The next prime is 1388731453. The reversal of 1388731428 is 8241378831.

It is a super-2 number, since 2×1388731428² = 3857149958229838368, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1388731423) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 127576 + ... + 138032.

It is an arithmetic number, because the mean of its divisors is an integer number (30453696).

Almost surely, 2^1388731428 is an apocalyptic number.

1388731428 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 1388731428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2192666112).

1388731428 is an abundant number, since it is smaller than the sum of its proper divisors (2996600796).

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

1388731428 is a wasteful number, since it uses less digits than its factorization.

1388731428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10522 (or 10517 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The square root of 1388731428 is about 37265.6870056088. The cubic root of 1388731428 is about 1115.6794180738.

The spelling of 1388731428 in words is "one billion, three hundred eighty-eight million, seven hundred thirty-one thousand, four hundred twenty-eight".