1681627993 has 4 divisors (see below), whose sum is σ = 1717407360. Its totient is φ = 1645848628.

The previous prime is 1681627979. The next prime is 1681627999. The reversal of 1681627993 is 3997261861.

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: 3997261861 = 31 ⋅128943931.

It is a cyclic number.

It is not a de Polignac number, because 1681627993 - 2²¹ = 1679530841 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1681627993.

It is not an unprimeable number, because it can be changed into a prime (1681627999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17889613 + ... + 17889706.

It is an arithmetic number, because the mean of its divisors is an integer number (429351840).

Almost surely, 2^1681627993 is an apocalyptic number.

It is an amenable number.

1681627993 is a deficient number, since it is larger than the sum of its proper divisors (35779367).

1681627993 is an equidigital number, since it uses as much as digits as its factorization.

1681627993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35779366.

The product of its digits is 979776, while the sum is 52.

The square root of 1681627993 is about 41007.6577360863. The cubic root of 1681627993 is about 1189.1682611602.

The spelling of 1681627993 in words is "one billion, six hundred eighty-one million, six hundred twenty-seven thousand, nine hundred ninety-three".