1981571 has 8 divisors (see below), whose sum is σ = 2150064. Its totient is φ = 1818880.

The previous prime is 1981547. The next prime is 1981583. The reversal of 1981571 is 1751891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 725 + ... + 2118.

It is an arithmetic number, because the mean of its divisors is an integer number (268758).

2^1981571 is an apocalyptic number.

1981571 is a deficient number, since it is larger than the sum of its proper divisors (168493).

1981571 is a wasteful number, since it uses less digits than its factorization.

1981571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2901.

The product of its digits is 2520, while the sum is 32.

The square root of 1981571 is about 1407.6828478034. The cubic root of 1981571 is about 125.6039254930.

It can be divided in two parts, 1981 and 571, that added together give a palindrome (2552).

The spelling of 1981571 in words is "one million, nine hundred eighty-one thousand, five hundred seventy-one".