1387988817 has 32 divisors (see below), whose sum is σ = 2093529600. Its totient is φ = 812706048.

The previous prime is 1387988813. The next prime is 1387988821. The reversal of 1387988817 is 7188897831.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1387988813) and next prime (1387988821).

It is not a de Polignac number, because 1387988817 - 2² = 1387988813 is a prime.

It is a super-2 number, since 2×1387988817² = 3853025912234118978, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1387988813) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54234 + ... + 75612.

It is an arithmetic number, because the mean of its divisors is an integer number (65422800).

Almost surely, 2^1387988817 is an apocalyptic number.

1387988817 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1387988817 is a deficient number, since it is larger than the sum of its proper divisors (705540783).

1387988817 is a wasteful number, since it uses less digits than its factorization.

1387988817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21485.

The product of its digits is 5419008, while the sum is 60.

The square root of 1387988817 is about 37255.7219363684. The cubic root of 1387988817 is about 1115.4805162762.

The spelling of 1387988817 in words is "one billion, three hundred eighty-seven million, nine hundred eighty-eight thousand, eight hundred seventeen".