1799991 has 6 divisors (see below), whose sum is σ = 2600000. Its totient is φ = 1199988.

The previous prime is 1799983. The next prime is 1799999. The reversal of 1799991 is 1999971.

It is an interprime number because it is at equal distance from previous prime (1799983) and next prime (1799999).

It is not a de Polignac number, because 1799991 - 2³ = 1799983 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 (1799999) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 99991 + ... + 100008.

2^1799991 is an apocalyptic number.

1799991 is a deficient number, since it is larger than the sum of its proper divisors (800009).

1799991 is a wasteful number, since it uses less digits than its factorization.

1799991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200005 (or 200002 counting only the distinct ones).

The product of its digits is 45927, while the sum is 45.

The square root of 1799991 is about 1341.6374323937. The cubic root of 1799991 is about 121.6438371711.

The spelling of 1799991 in words is "one million, seven hundred ninety-nine thousand, nine hundred ninety-one".