1399987665 has 16 divisors (see below), whose sum is σ = 2488867200. Its totient is φ = 746660016.

The previous prime is 1399987663. The next prime is 1399987691. The reversal of 1399987665 is 5667899931.

It is not a de Polignac number, because 1399987665 - 2¹ = 1399987663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1399987663) 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, 5185005 + ... + 5185274.

It is an arithmetic number, because the mean of its divisors is an integer number (155554200).

Almost surely, 2^1399987665 is an apocalyptic number.

1399987665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1399987665 is a deficient number, since it is larger than the sum of its proper divisors (1088879535).

1399987665 is a wasteful number, since it uses less digits than its factorization.

1399987665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10370293 (or 10370287 counting only the distinct ones).

The product of its digits is 22044960, while the sum is 63.

The square root of 1399987665 is about 37416.4090340054. The cubic root of 1399987665 is about 1118.6856565889.

The spelling of 1399987665 in words is "one billion, three hundred ninety-nine million, nine hundred eighty-seven thousand, six hundred sixty-five".