1388807440 has 80 divisors (see below), whose sum is σ = 3347642880. Its totient is φ = 535265280.

The previous prime is 1388807437. The next prime is 1388807447. The reversal of 1388807440 is 447088831.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×1388807440² = 3857572210798707200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1388807447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 636271 + ... + 638449.

It is an arithmetic number, because the mean of its divisors is an integer number (41845536).

Almost surely, 2^1388807440 is an apocalyptic number.

1388807440 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 1388807440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1673821440).

1388807440 is an abundant number, since it is smaller than the sum of its proper divisors (1958835440).

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

1388807440 is a wasteful number, since it uses less digits than its factorization.

1388807440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2480 (or 2474 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 43.

The square root of 1388807440 is about 37266.7068574619. The cubic root of 1388807440 is about 1115.6997732159.

The spelling of 1388807440 in words is "one billion, three hundred eighty-eight million, eight hundred seven thousand, four hundred forty".