1387681 has 2 divisors, whose sum is σ = 1387682. Its totient is φ = 1387680.

The previous prime is 1387669. The next prime is 1387691. The reversal of 1387681 is 1867831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1380625 + 7056 = 1175^2 + 84^2 .

It is a cyclic number.

It is not a de Polignac number, because 1387681 - 2⁵ = 1387649 is a prime.

It is a super-2 number, since 2×1387681² = 3851317115522, which contains 22 as substring.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (1387601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693840 + 693841.

It is an arithmetic number, because the mean of its divisors is an integer number (693841).

2^1387681 is an apocalyptic number.

It is an amenable number.

1387681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1387681 is an equidigital number, since it uses as much as digits as its factorization.

1387681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 34.

The square root of 1387681 is about 1177.9987266547. The cubic root of 1387681 is about 111.5398049413.

The spelling of 1387681 in words is "one million, three hundred eighty-seven thousand, six hundred eighty-one".