1388742840 has 256 divisors, whose sum is σ = 4790016000. Its totient is φ = 357696000.

The previous prime is 1388742827. The next prime is 1388742863. The reversal of 1388742840 is 482478831.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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 63 ways as a sum of consecutive naturals, for example, 5532715 + ... + 5532965.

It is an arithmetic number, because the mean of its divisors is an integer number (18711000).

Almost surely, 2^1388742840 is an apocalyptic number.

1388742840 is a gapful number since it is divisible by the number (10) 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 1388742840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2395008000).

1388742840 is an abundant number, since it is smaller than the sum of its proper divisors (3401273160).

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

1388742840 is a wasteful number, since it uses less digits than its factorization.

1388742840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427 (or 417 counting only the distinct ones).

The product of its (nonzero) digits is 344064, while the sum is 45.

The square root of 1388742840 is about 37265.8401220206. The cubic root of 1388742840 is about 1115.6824741240.

The spelling of 1388742840 in words is "one billion, three hundred eighty-eight million, seven hundred forty-two thousand, eight hundred forty".