1991018 has 8 divisors (see below), whose sum is σ = 3116448. Its totient is φ = 952204.

The previous prime is 1990987. The next prime is 1991027. The reversal of 1991018 is 8101991.

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

It is a Curzon number.

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 3 ways as a sum of consecutive naturals, for example, 21596 + ... + 21687.

It is an arithmetic number, because the mean of its divisors is an integer number (389556).

2^1991018 is an apocalyptic number.

1991018 is a deficient number, since it is larger than the sum of its proper divisors (1125430).

1991018 is a wasteful number, since it uses less digits than its factorization.

1991018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43308.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 1991018 is about 1411.0343723666. The cubic root of 1991018 is about 125.8032117523.

The spelling of 1991018 in words is "one million, nine hundred ninety-one thousand, eighteen".