1996991 has 4 divisors (see below), whose sum is σ = 1999992. Its totient is φ = 1993992.

The previous prime is 1996979. The next prime is 1997003.

It is a happy number.

1996991 is nontrivially palindromic in base 10.

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

It is an interprime number because it is at equal distance from previous prime (1996979) and next prime (1997003).

It is a cyclic number.

It is not a de Polignac number, because 1996991 - 2¹⁰ = 1995967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1996901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5 + ... + 1998.

It is an arithmetic number, because the mean of its divisors is an integer number (499998).

2^1996991 is an apocalyptic number.

1996991 is a deficient number, since it is larger than the sum of its proper divisors (3001).

1996991 is an equidigital number, since it uses as much as digits as its factorization.

1996991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3000.

The product of its digits is 39366, while the sum is 44.

The square root of 1996991 is about 1413.1493197819. The cubic root of 1996991 is about 125.9288882350.

The spelling of 1996991 in words is "one million, nine hundred ninety-six thousand, nine hundred ninety-one".