1680931393 has 4 divisors (see below), whose sum is σ = 1682218800. Its totient is φ = 1679643988.

The previous prime is 1680931391. The next prime is 1680931397. The reversal of 1680931393 is 3931390861.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3931390861 = 27077 ⋅145193.

It is a cyclic number.

It is not a de Polignac number, because 1680931393 - 2¹ = 1680931391 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1680931391) 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 3 ways as a sum of consecutive naturals, for example, 641743 + ... + 644356.

It is an arithmetic number, because the mean of its divisors is an integer number (420554700).

Almost surely, 2^1680931393 is an apocalyptic number.

It is an amenable number.

1680931393 is a deficient number, since it is larger than the sum of its proper divisors (1287407).

1680931393 is a wasteful number, since it uses less digits than its factorization.

1680931393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1287406.

The product of its (nonzero) digits is 104976, while the sum is 43.

The square root of 1680931393 is about 40999.1633207313. The cubic root of 1680931393 is about 1189.0040375581.

The spelling of 1680931393 in words is "one billion, six hundred eighty million, nine hundred thirty-one thousand, three hundred ninety-three".