1691394439 has 16 divisors (see below), whose sum is σ = 1949075712. Its totient is φ = 1437766848.

The previous prime is 1691394437. The next prime is 1691394457. The reversal of 1691394439 is 9344931961.

It is a happy number.

It is not a de Polignac number, because 1691394439 - 2¹ = 1691394437 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1691394392 and 1691394401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1691394433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 641067 + ... + 643699.

It is an arithmetic number, because the mean of its divisors is an integer number (121817232).

Almost surely, 2^1691394439 is an apocalyptic number.

1691394439 is a deficient number, since it is larger than the sum of its proper divisors (257681273).

1691394439 is a wasteful number, since it uses less digits than its factorization.

1691394439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3366.

The product of its digits is 629856, while the sum is 49.

The square root of 1691394439 is about 41126.5660978400. The cubic root of 1691394439 is about 1191.4659426038.

The spelling of 1691394439 in words is "one billion, six hundred ninety-one million, three hundred ninety-four thousand, four hundred thirty-nine".