1691389 has 16 divisors (see below), whose sum is σ = 2032128. Its totient is φ = 1377792.

The previous prime is 1691387. The next prime is 1691401. The reversal of 1691389 is 9831961.

It is a cyclic number.

It is not a de Polignac number, because 1691389 - 2¹ = 1691387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1691387) 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, 17389 + ... + 17485.

It is an arithmetic number, because the mean of its divisors is an integer number (127008).

2^1691389 is an apocalyptic number.

It is an amenable number.

1691389 is a deficient number, since it is larger than the sum of its proper divisors (340739).

1691389 is an equidigital number, since it uses as much as digits as its factorization.

1691389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204.

The product of its digits is 11664, while the sum is 37.

The square root of 1691389 is about 1300.5341210441. The cubic root of 1691389 is about 119.1464665474.

It can be divided in two parts, 1691 and 389, that added together give a triangular number (2080 = T₆₄).

The spelling of 1691389 in words is "one million, six hundred ninety-one thousand, three hundred eighty-nine".