1399987666 has 48 divisors (see below), whose sum is σ = 2644967808. Its totient is φ = 544008960.

The previous prime is 1399987663. The next prime is 1399987691. The reversal of 1399987666 is 6667899931.

It is a junction number, because it is equal to n+sod(n) for n = 1399987598 and 1399987607.

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 23 ways as a sum of consecutive naturals, for example, 824130 + ... + 825826.

It is an arithmetic number, because the mean of its divisors is an integer number (55103496).

Almost surely, 2^1399987666 is an apocalyptic number.

1399987666 is a deficient number, since it is larger than the sum of its proper divisors (1244980142).

1399987666 is a wasteful number, since it uses less digits than its factorization.

1399987666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2215 (or 2204 counting only the distinct ones).

The product of its digits is 26453952, while the sum is 64.

The square root of 1399987666 is about 37416.4090473685. The cubic root of 1399987666 is about 1118.6856568552.

The spelling of 1399987666 in words is "one billion, three hundred ninety-nine million, nine hundred eighty-seven thousand, six hundred sixty-six".