1968991 has 4 divisors (see below), whose sum is σ = 2084832. Its totient is φ = 1853152.

The previous prime is 1968983. The next prime is 1968997. The reversal of 1968991 is 1998691.

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

It is a cyclic number.

It is not a de Polignac number, because 1968991 - 2³ = 1968983 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 (1968997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57895 + ... + 57928.

It is an arithmetic number, because the mean of its divisors is an integer number (521208).

2^1968991 is an apocalyptic number.

1968991 is a deficient number, since it is larger than the sum of its proper divisors (115841).

1968991 is a wasteful number, since it uses less digits than its factorization.

1968991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115840.

The product of its digits is 34992, while the sum is 43.

The square root of 1968991 is about 1403.2073973579. The cubic root of 1968991 is about 125.3375622599.

The spelling of 1968991 in words is "one million, nine hundred sixty-eight thousand, nine hundred ninety-one".