1981717 has 4 divisors (see below), whose sum is σ = 1987776. Its totient is φ = 1975660.

The previous prime is 1981711. The next prime is 1981739. The reversal of 1981717 is 7171891.

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 1981717 - 2⁷ = 1981589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981711) 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, 2509 + ... + 3202.

It is an arithmetic number, because the mean of its divisors is an integer number (496944).

2^1981717 is an apocalyptic number.

It is an amenable number.

1981717 is a deficient number, since it is larger than the sum of its proper divisors (6059).

1981717 is an equidigital number, since it uses as much as digits as its factorization.

1981717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6058.

The product of its digits is 3528, while the sum is 34.

The square root of 1981717 is about 1407.7347051203. The cubic root of 1981717 is about 125.6070102042.

The spelling of 1981717 in words is "one million, nine hundred eighty-one thousand, seven hundred seventeen".