1389691 has 4 divisors (see below), whose sum is σ = 1393272. Its totient is φ = 1386112.

The previous prime is 1389677. The next prime is 1389697. The reversal of 1389691 is 1969831.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1389691 is a prime.

It is a Duffinian number.

1389691 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1389691.

It is not an unprimeable number, because it can be changed into a prime (1389697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1126 + ... + 2011.

It is an arithmetic number, because the mean of its divisors is an integer number (348318).

2^1389691 is an apocalyptic number.

1389691 is a deficient number, since it is larger than the sum of its proper divisors (3581).

1389691 is an equidigital number, since it uses as much as digits as its factorization.

1389691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3580.

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

The square root of 1389691 is about 1178.8515597818. The cubic root of 1389691 is about 111.5936325979.

It can be divided in two parts, 1389 and 691, that added together give a triangular number (2080 = T₆₄).

The spelling of 1389691 in words is "one million, three hundred eighty-nine thousand, six hundred ninety-one".