1387888640 has 128 divisors (see below), whose sum is σ = 3425645520. Its totient is φ = 539492352.

The previous prime is 1387888549. The next prime is 1387888643. The reversal of 1387888640 is 468887831.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1387888643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7045022 + ... + 7045218.

Almost surely, 2^1387888640 is an apocalyptic number.

1387888640 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 1387888640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1712822760).

1387888640 is an abundant number, since it is smaller than the sum of its proper divisors (2037756880).

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

1387888640 is an frugal number, since it uses more digits than its factorization.

1387888640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275 (or 247 counting only the distinct ones).

The product of its (nonzero) digits is 2064384, while the sum is 53.

The square root of 1387888640 is about 37254.3774609106. The cubic root of 1387888640 is about 1115.4536793212.

The spelling of 1387888640 in words is "one billion, three hundred eighty-seven million, eight hundred eighty-eight thousand, six hundred forty".