1991002 has 16 divisors (see below), whose sum is σ = 3263400. Its totient is φ = 905472.

The previous prime is 1990987. The next prime is 1991027. The reversal of 1991002 is 2001991.

It can be written as a sum of positive squares in 4 ways, for example, as 1798281 + 192721 = 1341^2 + 439^2 .

It is an unprimeable number.

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, 1374 + ... + 2422.

2^1991002 is an apocalyptic number.

1991002 is a deficient number, since it is larger than the sum of its proper divisors (1272398).

1991002 is a wasteful number, since it uses less digits than its factorization.

1991002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1137.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 1991002 is about 1411.0287027555. The cubic root of 1991002 is about 125.8028747627.

Adding to 1991002 its reverse (2001991), we get a palindrome (3992993).

The spelling of 1991002 in words is "one million, nine hundred ninety-one thousand, two".