1981747 has 4 divisors (see below), whose sum is σ = 2000376. Its totient is φ = 1963120.

The previous prime is 1981739. The next prime is 1981753. The reversal of 1981747 is 7471891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1981747 - 2³ = 1981739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981787) 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, 9154 + ... + 9367.

It is an arithmetic number, because the mean of its divisors is an integer number (500094).

2^1981747 is an apocalyptic number.

1981747 is a deficient number, since it is larger than the sum of its proper divisors (18629).

1981747 is a wasteful number, since it uses less digits than its factorization.

1981747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18628.

The product of its digits is 14112, while the sum is 37.

The square root of 1981747 is about 1407.7453604967. The cubic root of 1981747 is about 125.6076440302.

The spelling of 1981747 in words is "one million, nine hundred eighty-one thousand, seven hundred forty-seven".