1691387 has 2 divisors, whose sum is σ = 1691388. Its totient is φ = 1691386.

The previous prime is 1691369. The next prime is 1691401. The reversal of 1691387 is 7831961.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1691387 - 2¹⁶ = 1625851 is a prime.

It is not a weakly prime, because it can be changed into another prime (1691087) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 845693 + 845694.

It is an arithmetic number, because the mean of its divisors is an integer number (845694).

2^1691387 is an apocalyptic number.

1691387 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691387 is an equidigital number, since it uses as much as digits as its factorization.

1691387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 35.

The square root of 1691387 is about 1300.5333521290. The cubic root of 1691387 is about 119.1464195854.

The spelling of 1691387 in words is "one million, six hundred ninety-one thousand, three hundred eighty-seven".