1681820017 has 4 divisors (see below), whose sum is σ = 1770336880. Its totient is φ = 1593303156.

The previous prime is 1681819973. The next prime is 1681820033. The reversal of 1681820017 is 7100281861.

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.

It is a cyclic number.

It is not a de Polignac number, because 1681820017 - 2²⁷ = 1547602289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1681820117) 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, 44258403 + ... + 44258440.

It is an arithmetic number, because the mean of its divisors is an integer number (442584220).

Almost surely, 2^1681820017 is an apocalyptic number.

It is an amenable number.

1681820017 is a deficient number, since it is larger than the sum of its proper divisors (88516863).

1681820017 is an equidigital number, since it uses as much as digits as its factorization.

1681820017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88516862.

The product of its (nonzero) digits is 5376, while the sum is 34.

The square root of 1681820017 is about 41009.9989880517. The cubic root of 1681820017 is about 1189.2135228859.

The spelling of 1681820017 in words is "one billion, six hundred eighty-one million, eight hundred twenty thousand, seventeen".