1991006 has 16 divisors (see below), whose sum is σ = 3265920. Its totient is φ = 906240.

The previous prime is 1990987. The next prime is 1991027. The reversal of 1991006 is 6001991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110 + ... + 1998.

It is an arithmetic number, because the mean of its divisors is an integer number (204120).

2^1991006 is an apocalyptic number.

1991006 is a deficient number, since it is larger than the sum of its proper divisors (1274914).

1991006 is a wasteful number, since it uses less digits than its factorization.

1991006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 1991006 is about 1411.0301201604. The cubic root of 1991006 is about 125.8029590103.

Adding to 1991006 its reverse (6001991), we get a palindrome (7992997).

The spelling of 1991006 in words is "one million, nine hundred ninety-one thousand, six".